APT Actors Exploiting Newly Identified Vulnerability in ManageEngine ADSelfService Plus

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Summary

This Joint Cybersecurity Advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, Version 8. See the ATT&CK for Enterprise for  referenced threat actor tactics and for techniques.

This joint advisory is the result of analytic efforts between the Federal Bureau of Investigation (FBI), United States Coast Guard Cyber Command (CGCYBER), and the Cybersecurity and Infrastructure Security Agency (CISA) to highlight the cyber threat associated with active exploitation of a newly identified vulnerability (CVE-2021-40539) in ManageEngine ADSelfService Plus—a self-service password management and single sign-on solution.

CVE-2021-40539, rated critical by the Common Vulnerability Scoring System (CVSS), is an authentication bypass vulnerability affecting representational state transfer (REST) application programming interface (API) URLs that could enable remote code execution. The FBI, CISA, and CGCYBER assess that advanced persistent threat (APT) cyber actors are likely among those exploiting the vulnerability. The exploitation of ManageEngine ADSelfService Plus poses a serious risk to critical infrastructure companies, U.S.-cleared defense contractors, academic institutions, and other entities that use the software. Successful exploitation of the vulnerability allows an attacker to place webshells, which enable the adversary to conduct post-exploitation activities, such as compromising administrator credentials, conducting lateral movement, and exfiltrating registry hives and Active Directory files.

Zoho ManageEngine ADSelfService Plus build 6114, which Zoho released on September 6, 2021, fixes CVE-2021-40539. FBI, CISA, and CGCYBER strongly urge users and administrators to update to ADSelfService Plus build 6114. Additionally, FBI, CISA, and CGCYBER strongly urge organizations ensure ADSelfService Plus is not directly accessible from the internet.

The FBI, CISA, and CGCYBER have reports of malicious cyber actors using exploits against CVE-2021-40539 to gain access [T1190] to ManageEngine ADSelfService Plus, as early as August 2021. The actors have been observed using various tactics, techniques, and procedures (TTPs), including:

  • Frequently writing webshells [T1505.003] to disk for initial persistence
  • Obfuscating and Deobfuscating/Decoding Files or Information  [T1027 and T1140]
  • Conducting further operations to dump user credentials [T1003]
  • Living off the land by only using signed Windows binaries for follow-on actions [T1218]
  • Adding/deleting user accounts as needed [T1136]
  • Stealing copies of the Active Directory database (NTDS.dit) [T1003.003] or registry hives
  • Using Windows Management Instrumentation (WMI) for remote execution [T1047]
  • Deleting files to remove indicators from the host [T1070.004]
  • Discovering domain accounts with the net Windows command [1087.002]
  • Using Windows utilities to collect and archive files for exfiltration [T1560.001]
  • Using custom symmetric encryption for command and control (C2) [T1573.001]

The FBI, CISA, and CGCYBER are proactively investigating and responding to this malicious cyber activity.

  • FBI is leveraging specially trained cyber squads in each of its 56 field offices and CyWatch, the FBI’s 24/7 operations center and watch floor, which provides around-the-clock support to track incidents and communicate with field offices across the country and partner agencies.
  • CISA offers a range of no-cost cyber hygiene services to help organizations assess, identify, and reduce their exposure to threats. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate attack vectors.
  • CGCYBER has deployable elements that provide cyber capability to marine transportation system critical infrastructure in proactive defense or response to incidents.

Sharing technical and/or qualitative information with the FBI, CISA, and CGCYBER helps empower and amplify our capabilities as federal partners to collect and share intelligence and engage with victims while working to unmask and hold accountable, those conducting malicious cyber activities. See the Contact section below for details.

Click here for a PDF version of this report.

Click here for indicators of compromise (IOCs) in STIX format.

Technical Details

Successful compromise of ManageEngine ADSelfService Plus, via exploitation of CVE-2021-40539, allows the attacker to upload a .zip file containing a JavaServer Pages (JSP) webshell masquerading as an x509 certificate: service.cer. Subsequent requests are then made to different API endpoints to further exploit the victim’s system.

After the initial exploitation, the JSP webshell is accessible at /help/admin-guide/Reports/ReportGenerate.jsp. The attacker then attempts to move laterally using Windows Management Instrumentation (WMI), gain access to a domain controller, dump NTDS.dit and SECURITY/SYSTEM registry hives, and then, from there, continues the compromised access.

Confirming a successful compromise of ManageEngine ADSelfService Plus may be difficult—the attackers run clean-up scripts designed to remove traces of the initial point of compromise and hide any relationship between exploitation of the vulnerability and the webshell.

Targeted Sectors

APT cyber actors have targeted academic institutions, defense contractors, and critical infrastructure entities in multiple industry sectors—including transportation, IT, manufacturing, communications, logistics, and finance. Illicitly obtained access and information may disrupt company operations and subvert U.S. research in multiple sectors.

Indicators of Compromise

Hashes:

068d1b3813489e41116867729504c40019ff2b1fe32aab4716d429780e666324
49a6f77d380512b274baff4f78783f54cb962e2a8a5e238a453058a351fcfbba

File paths:

C:ManageEngineADSelfService Pluswebappsadssphelpadmin-guidereportsReportGenerate.jsp
C:ManageEngineADSelfService Pluswebappsadssphtmlpromotionadap.jsp
C:ManageEngineADSelfService PlusworkCatalinalocalhostROOTorgapachejsphelp
C:ManageEngineADSelfService PlusjrebinSelfSe~1.key (filename varies with an epoch timestamp of creation, extension may vary as well)
C:ManageEngineADSelfService PluswebappsadsspCertificatesSelfService.csr
C:ManageEngineADSelfService Plusbinservice.cer
C:UsersPubliccustom.txt
C:UsersPubliccustom.bat
C:ManageEngineADSelfService PlusworkCatalinalocalhostROOTorgapachejsphelp (including subdirectories and contained files)

Webshell URL Paths:

/help/admin-guide/Reports/ReportGenerate.jsp

/html/promotion/adap.jsp

Check log files located at C:ManageEngineADSelfService Pluslogs for evidence of successful exploitation of the ADSelfService Plus vulnerability:

  • In access* logs:
    • /help/admin-guide/Reports/ReportGenerate.jsp
    • /ServletApi/../RestApi/LogonCustomization
    • /ServletApi/../RestAPI/Connection
  • In serverOut_* logs:
    • Keystore will be created for "admin"
    • The status of keystore creation is Upload!
  • In adslog* logs:
    • Java traceback errors that include references to NullPointerException in addSmartCardConfig or getSmartCardConfig

TTPs:

  • WMI for lateral movement and remote code execution (wmic.exe)
  • Using plaintext credentials acquired from compromised ADSelfService Plus host
  • Using pg_dump.exe to dump ManageEngine databases
  • Dumping NTDS.dit and SECURITY/SYSTEM/NTUSER registry hives
  • Exfiltration through webshells
  • Post-exploitation activity conducted with compromised U.S. infrastructure
  • Deleting specific, filtered log lines

Yara Rules:

rule ReportGenerate_jsp {
   strings:
      $s1 = “decrypt(fpath)”
      $s2 = “decrypt(fcontext)”
      $s3 = “decrypt(commandEnc)”
      $s4 = “upload failed!”
      $s5 = “sevck”
      $s6 = “newid”
   condition:
      filesize < 15KB and 4 of them
}

 

rule EncryptJSP {
   strings:
      $s1 = “AEScrypt”
      $s2 = “AES/CBC/PKCS5Padding”
      $s3 = “SecretKeySpec”
      $s4 = “FileOutputStream”
      $s5 = “getParameter”
      $s6 = “new ProcessBuilder”
      $s7 = “new BufferedReader”
      $s8 = “readLine()”
   condition:
      filesize < 15KB and 6 of them
}

Mitigations

Organizations that identify any activity related to ManageEngine ADSelfService Plus indicators of compromise within their networks should take action immediately.

Zoho ManageEngine ADSelfService Plus build 6114, which Zoho released on September 6, 2021, fixes CVE-2021-40539. FBI, CISA, and CGCYBER strongly urge users and administrators to update to ADSelfService Plus build 6114. Additionally, FBI, CISA, and CGCYBER strongly urge organizations ensure ADSelfService Plus is not directly accessible from the internet.

Additionally, FBI, CISA, and CGCYBER strongly recommend domain-wide password resets and double Kerberos Ticket Granting Ticket (TGT) password resets if any indication is found that the NTDS.dit file was compromised.

Actions for Affected Organizations

Immediately report as an incident to CISA or the FBI (refer to Contact Information section below) the existence of any of the following:

  • Identification of indicators of compromise as outlined above.
  • Presence of webshell code on compromised ManageEngine ADSelfService Plus servers.
  • Unauthorized access to or use of accounts.
  • Evidence of lateral movement by malicious actors with access to compromised systems.
  • Other indicators of unauthorized access or compromise.

Contact Information

Recipients of this report are encouraged to contribute any additional information that they may have related to this threat.

For any questions related to this report or to report an intrusion and request resources for incident response or technical assistance, please contact:

Revisions

September 16, 2021: Initial Version

Source…

Ransomware Awareness for Holidays and Weekends

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Immediate Actions You Can Take Now to Protect Against Ransomware
• Make an offline backup of your data.
• Do not click on suspicious links.
• If you use RDP, secure and monitor it.
Update your OS and software.
• Use strong passwords.
Use multi-factor authentication.

The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) have observed an increase in highly impactful ransomware attacks occurring on holidays and weekends—when offices are normally closed—in the United States, as recently as the Fourth of July holiday in 2021. The FBI and CISA do not currently have any specific threat reporting indicating a cyberattack will occur over the upcoming Labor Day holiday. However, the FBI and CISA are sharing the below information to provide awareness to be especially diligent in your network defense practices in the run up to holidays and weekends, based on recent actor tactics, techniques, and procedures (TTPs) and cyberattacks over holidays and weekends during the past few months. The FBI and CISA encourage all entities to examine their current cybersecurity posture and implement the recommended best practices and mitigations to manage the risk posed by all cyber threats, including ransomware.

Click here for a PDF copy of this report.

Threat Overview

Recent Holiday Targeting

Cyber actors have conducted increasingly impactful attacks against U.S. entities on or around holiday weekends over the last several months. The FBI and CISA do not currently have specific information regarding cyber threats coinciding with upcoming holidays and weekends. Cyber criminals, however, may view holidays and weekends—especially holiday weekends—as attractive timeframes in which to target potential victims, including small and large businesses. In some cases, this tactic provides a head start for malicious actors conducting network exploitation and follow-on propagation of ransomware, as network defenders and IT support of victim organizations are at limited capacity for an extended time.

  • In May 2021, leading into Mother’s Day weekend, malicious cyber actors deployed DarkSide ransomware against the IT network of a U.S.-based critical infrastructure entity in the Energy Sector, resulting in a week-long suspension of operations. After DarkSide actors gained access to the victim’s network, they deployed ransomware to encrypt victim data and—as a secondary form of extortion—exfiltrated the data before threatening to publish it to further pressure victims into paying the ransom demand.
  • In May 2021, over the Memorial Day weekend, a critical infrastructure entity in the Food and Agricultural Sector suffered a Sodinokibi/REvil ransomware attack affecting U.S. and Australian meat production facilities, resulting in a complete production stoppage.
  • In July 2021, during the Fourth of July holiday weekend, Sodinokibi/REvil ransomware actors attacked a U.S.-based critical infrastructure entity in the IT Sector and implementations of their remote monitoring and management tool, affecting hundreds of organizations—including multiple managed service providers and their customers.

Ransomware Trends

The FBI’s Internet Crime Complaint Center (IC3), which provides the public with a trustworthy source for reporting information on cyber incidents, received 791,790 complaints for all types of internet crime—a record number—from the American public in 2020, with reported losses exceeding $4.1 billion. This represents a 69 percent increase in total complaints from 2019. The number of ransomware incidents also continues to rise, with 2,474 incidents reported in 2020, representing a 20 percent increase in the number of incidents, and a 225 percent increase in ransom demands. From January to July 31, 2021, the IC3 has received 2,084 ransomware complaints with over $16.8M in losses, a 62 percent increase in reporting and 20 percent increase in reported losses compared to the same time frame in 2020.
  The following ransomware variants have been the most frequently reported to FBI in attacks over the last month.

  • Conti
  • PYSA
  • LockBit
  • RansomEXX/Defray777
  • Zeppelin
  • Crysis/Dharma/Phobos

The destructive impact of ransomware continues to evolve beyond encryption of IT assets. Cyber criminals have increasingly targeted large, lucrative organizations and providers of critical services with the expectation of higher value ransoms and increased likelihood of payments. Cyber criminals have also increasingly coupled initial encryption of data with a secondary form of extortion, in which they threaten to publicly name affected victims and release sensitive or proprietary data exfiltrated before encryption, to further encourage payment of ransom. (See CISA’s Fact Sheet: Protecting Sensitive and Personal Information from Ransomware-Caused Data Breaches.) Malicious actors have also added tactics, such as encrypting or deleting system backups—making restoration and recovery more difficult or infeasible for impacted organizations.

Although cyber criminals use a variety of techniques to infect victims with ransomware, the two most prevalent initial access vectors are phishing and brute forcing unsecured remote desktop protocol (RDP) endpoints. Additional common means of initial infection include deployment of precursor or dropper malware; exploitation of software or operating system vulnerabilities; exploitation of managed service providers with access to customer networks; and the use of valid, stolen credentials, such as those purchased on the dark web. Precursor malware enables cyber actors to conduct reconnaissance on victim networks, steal credentials, escalate privileges, exfiltrate information, move laterally on the victim network, and obfuscate command-and-control communications. Cyber actors use this access to: 

  • Evaluate a victim’s ability to pay a ransom.
  • Evaluate a victim’s incentive to pay a ransom to: 
    • Regain access to their data and/or 
    • Avoid having their sensitive or proprietary data publicly leaked.
  • Gather information for follow-on attacks before deploying ransomware on the victim network.

Threat Hunting

The FBI and CISA suggest organizations engage in preemptive threat hunting on their networks. Threat hunting is a proactive strategy to search for signs of threat actor activity to prevent attacks before they occur or to minimize damage in the event of a successful attack. Threat actors can be present on a victim network long before they lock down a system, alerting the victim to the ransomware attack. Threat actors often search through a network to find and compromise the most critical or lucrative targets. Many will exfiltrate large amounts of data. Threat hunting encompasses the following elements of understanding the IT environment by developing a baseline through a behavior-based analytics approach, evaluating data logs, and installing automated alerting systems. 

  • Understand the IT environment’s routine activity and architecture by establishing a baseline. By implementing a behavior-based analytics approach, an organization can better assess user, endpoint, and network activity patterns. This approach can help an organization remain alert on deviations from normal activity and detect anomalies. Understanding when users log in to the network—and from what location—can assist in identifying anomalies. Understanding the baseline environment—including the normal internal and external traffic—can also help in detecting anomalies. Suspicious traffic patterns are usually the first indicators of a network incident but cannot be detected without establishing a baseline for the corporate network.
  • Review data logs. Understand what standard performance looks like in comparison to suspicious or anomalous activity. Things to look for include:
    • Numerous failed file modifications,
    • Increased CPU and disk activity,
    • Inability to access certain files, and
    • Unusual network communications.
  • Employ intrusion prevention systems and automated security alerting systems—such as security information event management software, intrusion detection systems, and endpoint detection and response.
  • Deploy honeytokens and alert on their usage to detect lateral movement.

Indicators of suspicious activity that threat hunters should look for include:

  • Unusual inbound and outbound network traffic,
  • Compromise of administrator privileges or escalation of the permissions on an account,
  • Theft of login and password credentials,
  • Substantial increase in database read volume,
  • Geographical irregularities in access and log in patterns,
  • Attempted user activity during anomalous logon times, 
  • Attempts to access folders on a server that are not linked to the HTML within the pages of the web server, and
  • Baseline deviations in the type of outbound encrypted traffic since advanced persistent threat actors frequently encrypt exfiltration.

See the joint advisory from Australia, Canada, New Zealand, the United Kingdom, and the United States on Technical Approaches to Uncovering and Remediating Malicious Activity for additional guidance on hunting or investigating a network, and for common mistakes in incident handling. Also review the Ransomware Response Checklist in the CISA-MS-ISAC Joint Ransomware Guide.

Cyber Hygiene Services

CISA offers a range of no-cost cyber hygiene services—including vulnerability scanning and ransomware readiness assessments—to help critical infrastructure organizations assess, identify, and reduce their exposure to cyber threats. By taking advantage of these services, organizations of any size will receive recommendations on ways to reduce their risk and mitigate attack vectors. 

Ransomware Best Practices

The FBI and CISA strongly discourage paying a ransom to criminal actors. Payment does not guarantee files will be recovered, nor does it ensure protection from future breaches. Payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of malware, and/or fund illicit activities. Regardless of whether you or your organization decide to pay the ransom, the FBI and CISA urge you to report ransomware incidents to CISA, a local FBI field office, or by filing a report with IC3 at IC3.gov. Doing so provides the U.S. Government with critical information needed to help victims, track ransomware attackers, hold attackers accountable under U.S. law, and share information to prevent future attacks.

Information Requested

Upon receiving an incident report, the FBI or CISA may seek forensic artifacts, to the extent that affected entities determine such information can be legally shared, including: 

  • Recovered executable file(s),
  • Live memory (RAM) capture,
  • Images of infected systems,
  • Malware samples, and
  • Ransom note.

Recommended Mitigations

The FBI and CISA highly recommend organizations continuously and actively monitor for ransomware threats over holidays and weekends.
  Additionally, the FBI and CISA recommend identifying IT security employees to be available and “on call” during these times, in the event of a ransomware attack. The FBI and CISA also suggest applying the following network best practices to reduce the risk and impact of compromise.

Make an offline backup of your data.

  • Make and maintain offline, encrypted backups of data and regularly test your backups. Backup procedures should be conducted on a regular basis. It is important that backups be maintained offline as many ransomware variants attempt to find and delete or encrypt accessible backups.
  • Review your organization’s backup schedule to take into account the risk of a possible disruption to backup processes during weekends or holidays.

Do not click on suspicious links.

  • Implement a user training program and phishing exercises to raise awareness among users about the risks involved in visiting malicious websites or opening malicious attachments and to reinforce the appropriate user response to phishing and spearphishing emails.

If you use RDP—or other potentially risky services—secure and monitor.

  • Limit access to resources over internal networks, especially by restricting RDP and using virtual desktop infrastructure. After assessing risks, if RDP is deemed operationally necessary, restrict the originating sources and require MFA. If RDP must be available externally, it should be authenticated via VPN.
  • Monitor remote access/RDP logs, enforce account lockouts after a specified number of attempts, log RDP login attempts, and disable unused remote access/RDP ports.
  • Ensure devices are properly configured and that security features are enabled. Disable ports and protocols that are not being used for a business purpose (e.g., RDP Transmission Control Protocol Port 3389). 
  • Disable or block Server Message Block (SMB) protocol outbound and remove or disable outdated versions of SMB. Threat actors use SMB to propagate malware across organizations.
  • Review the security posture of third-party vendors and those interconnected with your organization. Ensure all connections between third-party vendors and outside software or hardware are monitored and reviewed for suspicious activity.
  • Implement listing policies for applications and remote access that only allow systems to execute known and permitted programs under an established security policy.
  • Open document readers in protected viewing modes to help prevent active content from running.

Update your OS and software; scan for vulnerabilities.

  • Upgrade software and operating systems that are no longer supported by vendors to currently supported versions. Regularly patch and update software to the latest available versions. Prioritize timely patching of internet-facing servers—as well as software processing internet data, such as web browsers, browser plugins, and document readers—for known vulnerabilities. Consider using a centralized patch management system; use a risk-based assessment strategy to determine which network assets and zones should participate in the patch management program.
  • Automatically update antivirus and anti-malware solutions and conduct regular virus and malware scans.
  • Conduct regular vulnerability scanning to identify and address vulnerabilities, especially those on internet-facing devices. (See the Cyber Hygiene Services section above for more information on CISA’s free services.)

Use strong passwords.

  • Ensure strong passwords and challenge responses. Passwords should not be reused across multiple accounts or stored on the system where an adversary may have access.

Use multi-factor authentication.

  • Require multi-factor authentication (MFA) for all services to the extent possible, particularly for remote access, virtual private networks, and accounts that access critical systems. 

Secure your network(s): implement segmentation, filter traffic, and scan ports.

  • Implement network segmentation with multiple layers, with the most critical communications occurring in the most secure and reliable layer.
  • Filter network traffic to prohibit ingress and egress communications with known malicious IP addresses. Prevent users from accessing malicious websites by implementing URL blocklists and/or allowlists.
  • Scan network for open and listening ports and close those that are unnecessary.
  • For companies with employees working remotely, secure home networks—including computing, entertainment, and Internet of Things devices—to prevent a cyberattack; use separate devices for separate activities; and do not exchange home and work content. 

Secure your user accounts.

  • Regularly audit administrative user accounts and configure access controls under the principles of least privilege and separation of duties.
  • Regularly audit logs to ensure new accounts are legitimate users.

Have an incident response plan.

  • Create, maintain, and exercise a basic cyber incident response plan that:
    • Includes procedures for response and notification in a ransomware incident and
    • Plans for the possibility of critical systems being inaccessible for a period of time.

Note: for help with developing your plan, review available incident response guidance, such as the Public Power Cyber Incident Response Playbook and the Ransomware Response Checklist in the CISA-MS-ISAC Joint Ransomware Guide.

If your organization is impacted by a ransomware incident, the FBI and CISA recommend the following actions.

  • Isolate the infected system. Remove the infected system from all networks, and disable the computer’s wireless, Bluetooth, and any other potential networking capabilities. Ensure all shared and networked drives are disconnected, whether wired or wireless.
  • Turn off other computers and devices. Power off and segregate (i.e., remove from the network) the infected computer(s). Power off and segregate any other computers or devices that share a network with the infected computer(s) that have not been fully encrypted by ransomware. If possible, collect and secure all infected and potentially infected computers and devices in a central location, making sure to clearly label any computers that have been encrypted. Powering off and segregating infected computers from computers that have not been fully encrypted may allow for the recovery of partially encrypted files by specialists.
  • Secure your backups. Ensure that your backup data is offline and secure. If possible, scan your backup data with an antivirus program to check that it is free of malware.

Additional Resources

For additional resources related to the prevention and mitigation of ransomware, go to https://www.stopransomware.gov as well as the CISA-Multi-State Information Sharing and Analysis Center (MS-ISAC) Joint Ransomware Guide. Stopransomware.gov is the U.S. Government’s new, official one-stop location for resources to tackle ransomware more effectively. Additional resources include:

Source…

BadAlloc Vulnerability Affecting BlackBerry QNX RTOS

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On August 17, 2021, BlackBerry publicly disclosed that its QNX Real Time Operating System (RTOS) is affected by a BadAlloc vulnerability—CVE-2021-22156. BadAlloc is a collection of vulnerabilities affecting multiple RTOSs and supporting libraries.[1] A remote attacker could exploit CVE-2021-22156 to cause a denial-of-service condition or execute arbitrary code on affected devices.[2] BlackBerry QNX RTOS is used in a wide range of products whose compromise could result in a malicious actor gaining control of highly sensitive systems,  increasing risk to the Nation’s critical functions. Note: at this time, CISA is not aware of active exploitation of this vulnerability.

CISA strongly encourages critical infrastructure organizations and other organization developing, maintaining, supporting, or using affected QNX-based systems, to patch affected products as quickly as possible. Refer to the Mitigations section for more information about patching.

CVE-2021-22156 is an integer overflow vulnerability affecting the calloc() function in the C runtime library of multiple BlackBerry QNX products. Exploitation of this vulnerability could lead to a denial-of-service condition or arbitrary code execution in affected devices. To exploit this vulnerability, an attacker must have control over the parameters to a calloc() function call and the ability to control what memory is accessed after the allocation. An attacker with network access could remotely exploit this vulnerability if the vulnerable product is running and the affected device is exposed to the internet.[3]

CVE-2021-22156 is part of a collection of integer overflow vulnerabilities, known as BadAlloc, which affect a wide range of industries using Internet of Things (IoT), and operational technology (OT)/industrial control systems (ICS) devices. See CISA ICS Advisory ICSA-21-119-04 and Microsoft’s BadAlloc blog post for more information.

All BlackBerry programs with dependency on the C runtime library are affected by this vulnerability (see table 1 for a list of affected BlackBerry QNX products). Because many affected devices include safety-critical devices, exploitation of this vulnerability could result in a malicious actor gaining control of sensitive systems, possibly leading to increased risk of damage to infrastructure or critical functions.

Table 1: Affected BlackBerry QNX Products [4]
Product Affected Version
 QNX SDP  6.5.0SP1, 6.5.0,  6.4.1, 6.4.0
 QNX Momentics Development Suite  6.3.2
 QNX Momentics 6.3.0SP3, 6.3.0SP2, 6.3.0SP1, 6.3.0, 6.2.1b, 6.2.1, 6.2.1A, 6.2.0
 QNX Realtime Platform  6.1.0a, 6.1.0, 6.0.0a, 6.0.0
 QNX Cross Development Kit  6.0.0, 6.1.0
 QNX Development Kit (Self-hosted)  6.0.0, 6.1.0
 QNX Neutrino RTOS Safe Kernel  1.0
 QNX Neutrino RTOS Certified Plus  1.0
 QNX Neutrino RTOS for Medical Devices  1.0, 1.1
 QNX OS for Automotive Safety  1.0
 QNX OS for Safety  1.0, 1.0.1
 QNX Neutrino Secure Kernel  6.4.0, 6.5.0
 QNX CAR Development Platform  2.0RR

 

CISA strongly encourages critical infrastructure organizations and other organizations developing, maintaining, supporting, or using affected QNX-based systems to patch affected products as quickly as possible.

  • Manufacturers of products that incorporate vulnerable versions should contact BlackBerry to obtain the patch.
  • Manufacturers of products who develop unique versions of RTOS software should contact BlackBerry to obtain the patch code. Note: in some cases, manufacturers may need to develop and test their own software patches.
  • End users of safety-critical systems should contact the manufacturer of their product to obtain a patch. If a patch is available, users should apply the patch as soon as possible. If a patch is not available, users should apply the manufacturer’s recommended mitigation measures until the patch can be applied.
    • Note: installation of software updates for RTOS frequently may require taking the device out of service or to an off-site location for physical replacement of integrated memory.

Resources

Source…

Top Routinely Exploited Vulnerabilities | CISA

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This Joint Cybersecurity Advisory was coauthored by the U.S. Cybersecurity and Infrastructure Security Agency (CISA), the Australian Cyber Security Centre (ACSC), the United Kingdom’s National Cyber Security Centre (NCSC), and the U.S. Federal Bureau of Investigation (FBI). 

This advisory provides details on the top 30 vulnerabilities—primarily Common Vulnerabilities and Exposures (CVEs)—routinely exploited by malicious cyber actors in 2020 and those being widely exploited thus far in 2021.  

Cyber actors continue to exploit publicly known—and often dated—software vulnerabilities against broad target sets, including public and private sector organizations worldwide. However, entities worldwide can mitigate the vulnerabilities listed in this report by applying the available patches to their systems and implementing a centralized patch management system. 

Click here for a PDF version of this report.

Key Findings

In 2020, cyber actors readily exploited recently disclosed vulnerabilities to compromise unpatched systems. Based on available data to the U.S. Government, a majority of the top vulnerabilities targeted in 2020 were disclosed during the past two years. Cyber actor exploitation of more recently disclosed software flaws in 2020 probably stems, in part, from the expansion of remote work options amid the COVID-19 pandemic. The rapid shift and increased use of remote work options, such as virtual private networks (VPNs) and cloud-based environments, likely placed additional burden on cyber defenders struggling to maintain and keep pace with routine software patching.

Four of the most targeted vulnerabilities in 2020 affected remote work, VPNs, or cloud-based technologies. Many VPN gateway devices remained unpatched during 2020, with the growth of remote work options challenging the ability of organization to conduct rigorous patch management.

CISA, ACSC, the NCSC, and FBI consider the vulnerabilities listed in table 1 to be the topmost regularly exploited CVEs by cyber actors during 2020. 

Table 1:Top Routinely Exploited CVEs in 2020

Vendor

CVE

Type

Citrix

CVE-2019-19781

arbitrary code execution

Pulse

CVE 2019-11510

arbitrary file reading

Fortinet

CVE 2018-13379

path traversal

F5- Big IP

CVE 2020-5902

remote code execution (RCE)

MobileIron

CVE 2020-15505

RCE

Microsoft

CVE-2017-11882

RCE

Atlassian

CVE-2019-11580

RCE

Drupal

CVE-2018-7600

RCE

Telerik

CVE 2019-18935

RCE

Microsoft

CVE-2019-0604

RCE

Microsoft

CVE-2020-0787

elevation of privilege

Netlogon

CVE-2020-1472

elevation of privilege

 

In 2021, malicious cyber actors continued to target vulnerabilities in perimeter-type devices. Among those highly exploited in 2021 are vulnerabilities in Microsoft, Pulse, Accellion, VMware, and Fortinet.

CISA, ACSC, the NCSC, and FBI assess that public and private organizations worldwide remain vulnerable to compromise from the exploitation of these CVEs. Malicious cyber actors will most likely continue to use older known vulnerabilities, such as CVE-2017-11882 affecting Microsoft Office, as long as they remain effective and systems remain unpatched. Adversaries’ use of known vulnerabilities complicates attribution, reduces costs, and minimizes risk because they are not investing in developing a zero-day exploit for their exclusive use, which they risk losing if it becomes known. 

Organizations are encouraged to remediate or mitigate vulnerabilities as quickly as possible to reduce the risk of exploitation. Most can be remediated by patching and updating systems. Organizations that have not remediated these vulnerabilities should investigate for the presence of IOCs and, if compromised, initiate incident response and recovery plans. See the Contact Information section below for how to reach CISA to report an incident or request technical assistance.

2020 CVEs

CISA, ACSC, the NCSC, and FBI have identified the following as the topmost exploited vulnerabilities by malicious cyber actors from 2020: CVE-2019-19781, CVE-2019-11510, CVE-2018-13379, CVE-2020-5902, CVE-2020-15505, CVE-2020-0688, CVE-2019-3396, CVE-2017-11882, CVE-2019-11580, CVE-2018-7600, CVE 2019-18935, CVE-2019-0604, CVE-2020-0787, CVE-2020-1472.[1][2][3] Among these vulnerabilities, CVE-2019-19781 was the most exploited flaw in 2020, according to U.S. Government technical analysis.CVE-2019-19781 is a recently disclosed critical vulnerability in Citrix’s Application Delivery Controller (ADC)—a load balancing application for web, application, and database servers widely use throughout the United States.[4][5] Nation-state and criminal cyber actors most likely favor using this vulnerability because it is easy to exploit, Citrix servers are widespread, and exploitation enables the actors to perform unauthorized RCE on a target system.[6

Identified as emerging targets in early 2020,[7] unremediated instances of CVE-2019-19781 and CVE-2019-11510 continued to be exploited throughout the year by nation-state advanced persistent threat actors (APTs) who leveraged these and other vulnerabilities, such as CVE-2018-13379[8][9], in VPN services[10][11] to compromise an array of organizations, including those involved in COVID-19 vaccine development.[12][13]

The CVE-2019-11510 vulnerability in Pulse Connect Secure VPN was also frequently targeted by nation-state APTs. Actors can exploit the vulnerability to steal the unencrypted credentials for all users on a compromised Pulse VPN server and retain unauthorized credentials for all users on a compromised Pulse VPN server and can retain unauthorize access after the system is patched unless all compromised credentials are changed. Nation-state APTs also commonly exploited CVE-2020-15505 and CVE-2020-5902.[14][15][16][17]

2021 CVEs

In 2021, cyber actors continued to target vulnerabilities in perimeter-type devices. In addition to the 2020 CVEs listed above, organizations should prioritize patching for the following CVEs known to be exploited. 

  • Microsoft Exchange: CVE-2021-26855, CVE-2021-26857, CVE-2021-26858, and CVE-2021-27065 
    • See CISA’s Alert: Mitigate Microsoft Exchange Server Vulnerabilities for more information on identifying and mitigating malicious activity concerning these vulnerabilities.
  • Pulse Secure: CVE-2021-22893, CVE-2021-22894, CVE-2021-22899, and CVE-2021-22900
    • See CISA’s Alert: Exploitation of Pulse Connect Secure Vulnerabilities for more information on how to investigate and mitigate this malicious activity.
  • Accellion: CVE-2021-27101, CVE-2021-27102, CVE-2021-27103, CVE-2021-27104
    • See the Australia-New Zealand-Singapore-UK-U.S. Joint Cybersecurity Advisory: Exploitation of Accellion File Transfer Appliance for technical details and mitigations.
  • VMware: CVE-2021-21985
    • See CISA’s Current Activity: Unpatched VMware vCenter Software for more information and guidance. 
  • Fortinet: CVE-2018-13379, CVE-2020-12812, and CVE-2019-5591 
    • See the CISA-FBI Joint Cybersecurity Advisory: APT Actors Exploit Vulnerabilities to Gain Initial Access for Future Attacks for more details and mitigations. 

Mitigations and Indicators of Compromise

One of the most effective best practices to mitigate many vulnerabilities is to update software versions once patches are available and as soon as is practicable. If this is not possible, consider applying temporary workarounds or other mitigations, if provided by the vendor. If an organization is unable to update all software shortly after a patch is released, prioritize implementing patches for CVEs that are already known to be exploited or that would be accessible to the largest number of potential attackers (such as internet-facing systems). This advisory highlights vulnerabilities that should be considered as part of the prioritization process. To further assist remediation, automatic software updates should be enabled whenever possible. 

Focusing scarce cyber defense resources on patching those vulnerabilities that cyber actors most often use offers the potential of bolstering network security while impeding our adversaries’ operations. For example, nation-state APTs in 2020 extensively relied on a single RCE vulnerability discovered in the Atlassian Crow, a centralized identity management and application (CVE-2019-11580) in its reported operations. A concerted focus on patching this vulnerability could have a relative broad impact by forcing the actors to find alternatives, which may not have the same broad applicability to their target set. 

Additionally, attackers commonly exploit weak authentication processes, particularly in external-facing devices. Organizations should require multi-factor authentication to remotely access networks from external sources, especially for administrator or privileged accounts.

Tables 2–14 provide more details about, and specific mitigations for, each of the top exploited CVEs in 2020. 

Note: The lists of associated malware corresponding to each CVE below are not meant to be exhaustive but intended to identify a malware family commonly associated with exploiting the CVE.
 

Table 2: CVE-2019-19781 Vulnerability Details

Citrix Netscaler Directory Traversal (CVE-2019-19781)

Vulnerability Description
Citrix Netscaler Application Delivery Control (ADC) is vulnerable to RCE and full system compromise due to poor access controls, thus allowing directory traversal. 

CVSS 3.02 

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

The lack of adequate access controls allows an attacker to enumerate system directories for vulnerable code (directory traversal). In this instance, Citrix ADC maintains a vulnerable Perl script (newbm.pl) that, when accessed via HTTP POST request (POST https://$TARGET/vpn/../vpn/portal/scripts/newbm.pl), allows local operating system (OS) commands to execute. Attackers can use this functionality to upload/execute command and control (C2) software (webshell or reverse-shell executable) using embedded commands (e.g., curl, wget, Invoke-WebRequest) and gain unauthorized access to the OS. 

Multiple malware campaigns, including NOTROBIN, have taken advantage of this vulnerability.

Fix

Patch Available

Recommended Mitigations

  • Implement the appropriate refresh build according to the vulnerability details outlined by the vendor: Citrix: Mitigation Steps for CVE-2019-19781
  • If possible, only allow the VPN to communicate with known Internet Protocol (IP) addresses (allow-list).

Detection Methods

Vulnerable Technologies and Versions
Citrix ADC and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0

References and Additional Guidance

 

Table 3: CVE 2019-11510 Vulnerability Details

 

Table 4: CVE 2018-13379 Vulnerability Details

 

Table 5: CVE-2020-5902 Vulnerability Details

F5 Big IP Traffic Management User Interface (CVE-2020-5902)

Vulnerability Description
The Traffic Management User Interface (TMUI), also referred to as the Configuration Utility, has an RCE vulnerability in undisclosed pages. 

CVSS 3.0
Critical

Vulnerability Discussion, IOCs, and Malware Campaigns
This vulnerability allows for unauthenticated attackers, or authenticated users, with network access to the Configuration Utility (through the BIG-IP management port and/or self IPs) to execute arbitrary system commands, create or delete files, disable services, and execute arbitrary Java code. This vulnerability may result in complete system compromise. The BIG-IP system in Appliance mode is also vulnerable. This issue is not exposed on the data plane; only the control plane is affected. 

Fix
Upgrade to Secure Versions Available
 

Recommended Mitigations
Download and install a fixed software version of the software from a vendor approved resource. If it is not possible to update quickly, restrict access via the following actions.

  • Address unauthenticated and authenticated attackers on self IPs by blocking all access.
  • Address unauthenticated attackers on management interface by restricting access. 
Detection Methods

Vulnerable Technologies and Versions
BIG-IP (LTM, AAM, Advanced WAF, AFM, Analytics, APM, ASM, DDHD, DNS, FPS, GTM, Link Controller, PEM, SSLO, CGNAT) 15.1.0, 15.0.0-15.0.1, 14.1.0-14.1.2, 13.1.0-13.1.3, 12.1.0-12.1.5, and 11.6.1-11.6.5 are vulnerable.

References

 

Table 6: CVE-2020-15505 Vulnerability Details

MobileIron Core & Connector (CVE-2020-15505)

Vulnerability Description

MobileIron Core & Connector, Sentry, and Monitoring and Reporting Database (RDB) software are vulnerable to RCE via unspecified vectors.

CVSS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

CVE-2020-15505 is an RCE vulnerability in MobileIron Core & Connector versions 10.3 and earlier. This vulnerability allows an external attacker, with no privileges, to execute code of their choice on the vulnerable system. As mobile device management (MDM) systems are critical to configuration management for external devices, they are usually highly permissioned and make a valuable target for threat actors.

Multiple APTs have been observed exploiting this vulnerability to gain unauthorized access.

Fix

Patch Available

Recommended Mitigations

  • Download and install a fixed software version of the software from a vendor approved resource.

Detection Methods

  • None. Manually check your software version to see if it is susceptible to this vulnerability. 

Vulnerable Technologies and Versions

MobileIron Core & Connector versions 10.3.0.3 and earlier, 10.4.0.0, 10.4.0.1, 10.4.0.2, 10.4.0.3, 10.5.1.0, 10.5.2.0, and 10.6.0.0; Sentry versions 9.7.2 and earlier and 9.8.0; and Monitor and Reporting Database (RDB) version 2.0.0.1 and earlier are vulnerable.

References

 

Table 7: CVE-2020-0688 Vulnerability Details

 

Table 8: CVE-2019-3396 Vulnerability Details

 

Table 9: CVE 2017-11882 Vulnerability Details

Microsoft Office Memory Corruption (CVE 2017-11882)

Vulnerability Description

Microsoft Office is prone to a memory corruption vulnerability allowing an attacker to run arbitrary code, in the context of the current user, by failing to properly handle objects in memory. It is also known as the “Microsoft Office Memory Corruption Vulnerability.” 

Cyber actors continued to exploit this four-year-old vulnerability in Microsoft Office that the U.S. Government publicly assessed last year was the most frequently targeted. Cyber actors most likely continue to exploit this vulnerability because Microsoft Office use is ubiquitous worldwide, the vulnerability is ideal for phasing campaigns, and it enables RCE on vulnerable systems.

CVSS 3.0

High

Vulnerability Discussion, IOCs, and Malware Campaigns

Microsoft Equation Editor, a component of Microsoft Office, contains a stack buffer overflow vulnerability that enables RCE on a vulnerable system. The component was compiled on November 9, 2000. Without any further recompilation, it was used in all currently supported versions of Microsoft Office. Microsoft Equation Editor is an out-of-process COM server that is hosted by eqnedt32.exe, meaning it runs as its own process and can accept commands from other processes.

Data execution prevention (DEP) and address space layout randomization (ASLR) should protect against such attacks. However, because of the manner in which eqnedt32.exe was linked, it will not use these features, subsequently allowing code execution. Being an out-of-process COM server, protections specific to Microsoft Office such as EMET and Windows Defender Exploit Guard are not applicable to eqnedt32.exe, unless applied system-wide. This provides the attacker with an avenue to lure targets into opening specially crafted documents, resulting in the ability to execute an embedded attacker commands.

Multiple cyber espionage campaigns have taken advantage of this vulnerability. CISA has noted CVE-2017-11882 being exploited to deliver LokiBot malware.

Fix

Patch Available

Recommended Mitigations

Detection Methods

  • Microsoft Defender Antivirus, Windows Defender, Microsoft Security Essentials, and the Microsoft Safety Scanner will all detect and patch this vulnerability.

Vulnerable Technologies and Versions

  • Microsoft Office 2007 Service Pack 3, Microsoft Office 2010 Service Pack 2, Microsoft Office 2013 Service Pack 1, and Microsoft Office 2016 are vulnerable.

References

 

Table 10: CVE 2019-11580 Vulnerability Details

Atlassian Crowd and Crowd Data Center Remote Code Execution (CVE 2019-11580)

Vulnerability Description

Atlassian Crowd and Crowd Data Center had the pdkinstall development plugin incorrectly enabled in release builds.

CVSS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

Attackers who can send unauthenticated or authenticated requests to a Crowd or Crowd Data Center instance can exploit this vulnerability to install arbitrary plugins, which permits RCE on systems running a vulnerable version of Crowd or Crowd Data Center.

Fix

Patch Available

Recommended Mitigations

  • Atlassian recommends customers running a version of Crowd below version 3.3.0 to upgrade to version 3.2.8. For customers running a version above or equal to 3.3.0, Atlassian recommends upgrading to the latest version.
  • Released Crowd and Crowd Data Center version 3.4.4 contains a fix for this issue and is available at https://www.atlassian.com/software/crowd/download.
  • Released Crowd and Crowd Data Center versions 3.0.5, 3.1.6, 3.2.8, and 3.3.5 contain a fix for this issue and are available at https://www.atlassian.com/software/crowd/download-archive.

Detection Methods

Vulnerable Technologies and Versions

All versions of Crowd from version 2.1.0 before 3.0.5 (the fixed version for 3.0.x), from version 3.1.0 before 3.1.6 (the fixed version for 3.1.x), from version 3.2.0 before 3.2.8 (the fixed version for 3.2.x), from version 3.3.0 before 3.3.5 (the fixed version for 3.3.x), and from version 3.4.0 before 3.4.4 (the fixed version for 3.4.x) are affected by this vulnerability.

References

 

Table 11: CVE 2018-7600 Vulnerability Details

Drupal Core Multiple Remote Code Execution (CVE 2018-7600)

Vulnerability Description

Drupal versions before 7.58, 8.x before 8.3.9, 8.4.x before 8.4.6, and 8.5.x before 8.5.1 allow remote attackers to execute arbitrary code because of an issue affecting multiple subsystems with default or common module configurations.

CVSS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

An RCE vulnerability exists within multiple subsystems of Drupal 7.x and 8.x. This potentially allows attackers to exploit multiple attack vectors on a Drupal site, which could result in the site being completely compromised. Failed exploit attempts may result in a denial-of-service condition. A remote user can send specially crafted data to trigger a flaw in the processing of renderable arrays in the Form Application Programming Interface, or API, and cause the target system to render the user-supplied data and execute arbitrary code on the target system.

Malware campaigns include the Muhstik botnet and XMRig Monero Cryptocurrency mining.

Fix

Patch Available

Recommended Mitigations

  • Upgrade to the most recent version of Drupal 7 or 8 core. If running 7.x, upgrade to Drupal 7.58. If running 8.5.x, upgrade to Drupal 8.5.1.

Detection Methods

Vulnerable Technologies and Versions

  • Drupal versions before 7.58, 8.x before 8.3.9, 8.4.x before 8.4.6, and 8.5.x before 8.5.1 are affected.

References

 

Table 12: CVE 2019-18935 Vulnerability Details

Telerik UI for ASP.NET AJAX Insecure Deserialization (CVE 2019-18935)

Vulnerability Description

Telerik User Interface (UI) for ASP.NET does not properly filter serialized input for malicious content. Versions prior to R1 2020 (2020.1.114) are susceptible to  remote code execution attacks on affected web servers due to a deserialization vulnerability.

CVS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

The Telerik UI does not properly sanitize serialized data inputs from the user. This vulnerability leads to the application being vulnerable to RCE attacks that may lead to a full system compromise. A vulnerable HTTP POST parameter rauPostData makes use of a vulnerable function/object AsyncUploadHandler. The object/function uses the JavaScriptSerializer.Deserialize() method, which not not properly sanitize the serialized data during the deserialization process. This issue is attacked by:

  1. Determining the vulnerable function is available/registered:  http://<HOST>/Telerik.Web.UI.WebResource.axd?type=rau,
  2. Determining if the version running is vulnerable by querying the UI, and
  3. Creating an object (e.g., malicious mixed-mode DLL with native OS commands or Reverse Shell) and uploading the object via rauPostData parameter along with the proper encryption key.

There were two malware campaigns associated with this vulnerability:

  • Netwalker Ransomware and
  • Blue Mockbird Monero Cryptocurrency-mining.

Fix

Patch Available

Recommended Mitigations

  • Update to the most recent version of Telerik UI for ASP.NET AJAX (at least 2020.1.114 or later).

Detection Methods

  • ACSC has an example PowerShell script that can be used to identify vulnerable Telerik UI DLLs on Windows web server hosts.
  • Vulnerable hosts should be reviewed for evidence of exploitation. Indicators of exploitation can be found in IIS HTTP request logs and within the Application Windows event log. Details of the above PowerShell script and exploitation detection recommendations are available in ACSC Advisory 2020-004.
  • Exploitation of this and previous Telerik UI vulnerabilities commonly resulted in the installation of web shell malware. NSA provides guidance on detecting and preventing web shell malware.

Vulnerable Technologies and Versions

Telerik UI for ASP.NET AJAX versions prior to R1 2020 (2020.1.114) are affected.

References

 

Table 13: CVE-2019-0604 Vulnerability Details

Microsoft SharePoint Remote Code Execution (CVE-2019-0604)

Vulnerability Description

A vulnerability in an XML deserialization component within Microsoft SharePoint allowed remote attackers to execute arbitrary code on vulnerable Microsoft SharePoint servers.

CVSS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

This vulnerability was typically exploited to install webshell malware to vulnerable hosts. A webshell could be placed in any location served by the associated Internet Information Services (IIS) web server and did not require authentication. These web shells would commonly be installed in the Layouts folder within the Microsoft SharePoint installation directory, for example:

C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions<version_number>TemplateLayouts

The xmlSerializer.Deserialize() method does not adequately sanitize user input that is received from the PickerEnitity/ValidateEnity (picker.aspx) functions in the serialized XML payloads. Once the serialized XML payload is deserialized, the XML code is evaulated for relevant XML commands and stings. A user can attack .Net based XML parsers with XMLNS payloads using the <system:string> tag and embedding malicious operating system commands. 

The exploit was used in malware phishing and the WickrMe/Hello Ransomware campaigns.

Fix

Patch Available

Recommended Mitigations

  • Upgrade on-premise installations of Microsoft Sharepoint to the latest available version (Microsoft SharePoint 2019) and patch level.
  • On-premise Microsoft SharePoint installations with a requirement to be accessed by internet-based remote staff should be moved behind an appropriate authentication mechanism such as a VPN, if possible.

Detection Methods

  • The patch level of on-premise Microsoft SharePoint installations should be reviewed for the presence of relevant security updates as outlined in the Microsoft SharePoint security advisory.
  • Vulnerable SharePoint servers should be reviewed for evidence of attempted exploitation. ACSC Advisory 2019-125 contains advice on reviewing IIS HTTP request logs for evidence of potential exploitation.
  • NSA provides guidance on detecting and preventing web shell malware.

Vulnerable Technologies and Versions

At the time of the vulnerability release, the following Microsoft SharePoint versions were affected: Microsoft Sharepoint 2019, Microsoft SharePoint 2016, Microsoft SharePoint 2013 SP1, and Microsoft SharePoint 2010 SP2.

References

 

Table 14: CVE-2020-0787 Vulnerability Details

Windows Background Intelligent Transfer Service Elevation of Privilege (CVE-2020-0787)

Vulnerability Description

The Windows Background Intelligent Transfer Service (BITS) is vulnerable to a privilege elevation vulnerability if it improperly handles symbolic links. An actor can exploit this vulnerability to execute arbitrary code with system-level privileges.

CVSS 3.0

High

Vulnerability Discussion, IOCs, and Malware Campaigns

To exploit this vulnerability, an actor would first need to have the ability to execute arbitrary code on a vulnerable Windows host.

Actors exploiting this vulnerability commonly used the proof of concept code released by the security researcher who discovered the vulnerability. If an actor left the proof of concept exploit’s working directories unchanged, then the presence of the following folders could be used as an indicator of exploitation:

C:Users<username>AppDataLocalTempworkspace
C:Users<username>AppDataLocalTempworkspacemountpoint
C:Users<username>AppDataLocalTempworkspacebait

The exploit was used in Maze and Egregor ransomware campaigns.

Fix

Patch Available

Recommended Mitigations

  • Apply the security updates as recommended in the Microsoft Netlogon security advisory.

Detection Methods

  • The patch level of all Microsoft Windows installations should be reviewed for the presence of relevant security updates as outlined in the Microsoft BITS security advisory.

Vulnerable Technologies and Versions

Windows 7 for 32-bit and x64-based Systems Service Pack 1, 8.1 for 32-bit and x64-based systems, RT 8.1, 10 for 32-bit and x64-based Systems, 10 1607 for 32-bit and x64-based Systems, 10 1709 for 32-bit and x64-based and ARM64-based Systems, 10 1803 for 32-bit and ARM64-based and x64-based Systems, 10 1809 for 32-bit and ARM64-based and x64-based Systems, 10 1903 for 32-bit and ARM64-based and x64-based Systems, 10 1909 for 32-bit, and ARM64-based and x64-based Systems are vulnerable.

Windows Server 2008 R2 for x64-based Systems Service Pack 1, 2008 R2 for x64-based Systems Service Pack 1 (Server Core Installation), 2008 for 32-bit Systems Service Pack 2, 2008 for 32-bit Systems Service Pack 2 (Server Core Installation), 2012, 2012 (Server Core Installation), 2012 R2, 2012 R2 (Server Core Installation), 2016, 2016 (Server Core Installation), 2019, 2019 (Server Core Installation), 1803 (Server Core Installation), 1903 (Server Core Installation), and 1909 (Server Core Installation) are also vulnerable.

References

 

Table 15: CVE-2020-1472 Vulnerability Details

Netlogon Elevation of Privilege (CVE-2020-1472)

Vulnerability Description

The Microsoft Windows Netlogon Remote Protocol (MS-NRPC) reuses a known, static, zero-value initialization vector (VI) in AES-CFB8 mode, which could allow an unauthenticated attacker to impersonate a domain-joined computer including a domain controller, and potentially obtain domain administrator privileges.

CVSS 3.0

Critical

Vulnerability Discussion, IOCs, and Malware Campaigns

To exploit this vulnerability, an actor would first need to have an existing presence on an internal network with network connectivity to a vulnerable Domain Controller, assuming that Domain Controllers are not exposed to the internet.

The immediate effect of successful exploitation results in the ability to authentication to the vulnerable Domain Controller with Domain Administrator level credentials. In compromises exploiting this vulnerability, exploitation was typically followed immediately by dumping all hashes for Domain accounts.

Threat actors were seen combining the MobileIron CVE-2020-15505 vulnerability for initial access, then using the Netlogon vulnerability to facilitate lateral movement and further compromise of target networks.

A nation-state APT group has been observed exploiting this vulnerability.[18]

Fix

Patch Available

Recommended Mitigations

  • Apply the security updates as recommended in the Microsoft Netlogon security advisory.

Detection Methods

  • The patch level of Domain Controllers should be reviewed for the presence of relevant security updates as outlined in the Microsoft Netlogon security advisory.
  • Reviewing and monitoring Windows Event Logs can identify potential exploitation attempts. However, further investigation would still be required to eliminate legitimate activity. Further information on these event logs is available in the ACSC 2020-016 Advisory.

Vulnerable Technologies and Versions

At the time of the vulnerability release, the following Microsoft Windows Server versions were vulnerable: all versions of Windows Server 2019; all versions of Windows Server 2016; Windows Server 2012 R2; Windows Server 2012; Windows Server 2008 R2 SP1; and Windows Server versions 1909/1903/1809.

References

 

For additional general best practices for mitigating cyber threats, see the joint advisory from Australia, Canada, New Zealand, the United Kingdom, and the United States on Technical Approaches to Uncovering and Remediating Malicious Activity and ACSC’s Essential Eight mitigation strategies.

Additional Resources

Free Cybersecurity Services

CISA offers several free cyber hygiene vulnerability scanning and web application services to help U.S. federal agencies, state and local governments, critical infrastructure, and private organizations reduce their exposure to threats by taking a proactive approach to mitigating attack vectors. For more information about CISA’s free services, or to sign up, email [email protected].

Cyber Essentials

CISA’s Cyber Essentials is a guide for leaders of small businesses as well as leaders of small and local government agencies to develop an actionable understanding of where to start implementing organizational cybersecurity practices.

Cyber.gov.au 

ACSC’s website provides advice and information about how to protect individuals and families, small- and medium-sized businesses, large organizations and infrastructure, and government organizations from cyber threats.

ACSC Partnership Program

The ACSC Partnership Program enables Australian organizations and individuals to engage with ACSC and fellow partners, drawing on collective understanding, experience, skills, and capability to lift cyber resilience across the Australian economy.

Australian organizations, including government and those in the private sector as well individuals, are welcome to sign up at Become an ACSC partner to join.

NCSC 10 Steps

The NCSC offers 10 Steps to Cyber Security, providing detailed guidance on how medium and large organizations can manage their security.

On vulnerabilities specifically, the NCSC has guidance to organizations on establishing an effective vulnerability management process, focusing on the management of widely available software and hardware.

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