Conti Ransomware | CISA

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Summary

Immediate Actions You Can Take Now to Protect Against Conti Ransomware
• Use multi-factor authentication.
• Segment and segregate networks and functions.
• Update your operating system and software.

Note: This Alert uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, version 9. See the ATT&CK for Enterprise for all referenced threat actor tactics and techniques.

The Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) have observed the increased use of Conti ransomware in more than 400 attacks on U.S. and international organizations. (See FBI Flash: Conti Ransomware Attacks Impact Healthcare and First Responder Networks.) In typical Conti ransomware attacks, malicious cyber actors steal files, encrypt servers and workstations, and demand a ransom payment. 

To secure systems against Conti ransomware, CISA, FBI, and the National Security Agency (NSA) recommend implementing the mitigation measures described in this Advisory, which include requiring multi-factor authentication (MFA), implementing network segmentation, and keeping operating systems and software up to date.

Click here for a PDF version of this report.

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

Technical Details

While Conti is considered a ransomware-as-a-service (RaaS) model ransomware variant, there is variation in its structure that differentiates it from a typical affiliate model. It is likely that Conti developers pay the deployers of the ransomware a wage rather than a percentage of the proceeds used by affiliate cyber actors and receives a share of the proceeds from a successful attack. 

Conti actors often gain initial access [TA0001] to networks through:

  • Spearphishing campaigns using tailored emails that contain malicious attachments [T1566.001] or malicious links [T1566.002];
    • Malicious Word attachments often contain embedded scripts that can be used to download or drop other malware—such as TrickBot and IcedID, and/or Cobalt Strike—to assist with lateral movement and later stages of the attack life cycle with the eventual goal of deploying Conti ransomware. [1],[2],[3]
  • Stolen or weak Remote Desktop Protocol (RDP) credentials [T1078].[4]
  • Phone calls;
  • Fake software promoted via search engine optimization;
  • Other malware distribution networks (e.g., ZLoader); and
  • Common vulnerabilities in external assets.

In the execution phase [TA0002], actors run a getuid payload before using a more aggressive payload to reduce the risk of triggering antivirus engines. CISA and FBI have observed Conti actors using Router Scan, a penetration testing tool, to maliciously scan for and brute force [T1110] routers, cameras, and network-attached storage devices with web interfaces. Additionally, actors use Kerberos attacks [T1558.003] to attempt to get the Admin hash to conduct brute force attacks.

Conti actors are known to exploit legitimate remote monitoring and management software and remote desktop software as backdoors to maintain persistence [TA0003] on victim networks.[5] The actors use tools already available on the victim network—and, as needed, add additional tools, such as Windows Sysinternals and Mimikatz—to obtain users’ hashes and clear-text credentials, which enable the actors to escalate privileges [TA0004] within a domain and perform other post-exploitation and lateral movement tasks [TA0008]. In some cases, the actors also use TrickBot malware to carry out post-exploitation tasks.

According to a recently leaked threat actor “playbook,” [6] Conti actors also exploit vulnerabilities in unpatched assets, such as the following, to escalate privileges [TA0004] and move laterally [TA0008] across a victim’s network:

  • 2017 Microsoft Windows Server Message Block 1.0 server vulnerabilities; [7]
  • “PrintNightmare” vulnerability (CVE-2021-34527) in Windows Print spooler [8] service; and
  • “Zerologon” vulnerability (CVE-2020-1472) in Microsoft Active Directory Domain Controller systems.[9]

Artifacts leaked with the playbook identify four Cobalt Strike server Internet Protocol (IP) addresses Conti actors previously used to communicate with their command and control (C2) server.

  • 162.244.80[.]235
  • 85.93.88[.]165
  • 185.141.63[.]120
  • 82.118.21[.]1

CISA and FBI have observed Conti actors using different Cobalt Strike server IP addresses unique to different victims.

Conti actors often use the open-source Rclone command line program for data exfiltration [TA0010]. After the actors steal and encrypt the victim’s sensitive data [T1486], they employ a double extortion technique in which they demand the victim pay a ransom for the release of the encrypted data and threaten the victim with public release of the data if the ransom is not paid.

MITRE ATT&CK Techniques

Conti ransomware uses the ATT&CK techniques listed in table 1.

Table 1: Conti ATT&CK techniques for enterprise
Technique Title ID Use
Valid Accounts T1078 Conti actors have been observed gaining unauthorized access to victim networks through stolen Remote Desktop Protocol (RDP) credentials. 
Phishing: Spearphishing Attachment  T1566.001 Conti ransomware can be delivered using TrickBot malware, which is known to use an email with an Excel sheet containing a malicious macro to deploy the malware.
Phishing: Spearphishing Link  T1566.002 Conti ransomware can be delivered using TrickBot, which has been delivered via malicious links in phishing emails.
Technique Title ID Use
Command and Scripting Interpreter: Windows Command Shell  T1059.003 Conti ransomware can utilize command line options to allow an attacker control over how it scans and encrypts files.
Native Application Programming Interface (API)  T1106 Conti ransomware has used API calls during execution.
Technique Title ID Use
Valid Accounts T1078 Conti actors have been observed gaining unauthorized access to victim networks through stolen RDP credentials. 
External Remote Services T1133 Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as virtual private networks (VPNs), Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management can also be used externally.
Technique Title ID Use
Process Injection: Dynamic-link Library Injection T1055.001 Conti ransomware has loaded an encrypted dynamic-link library (DLL) into memory and then executes it. 
Technique Title ID Use
Obfuscated Files or Information  T1027 Conti ransomware has encrypted DLLs and used obfuscation to hide Windows API calls.
Process Injection: Dynamic-link Library Injection T1055.001 Conti ransomware has loaded an encrypted DLL into memory and then executes it.
Deobfuscate/Decode Files or Information  T1140 Conti ransomware has decrypted its payload using a hardcoded AES-256 key.
Technique Title ID Use
Brute Force T1110 Conti actors use legitimate tools to maliciously scan for and brute force routers, cameras, and network-attached storage devices with web interfaces.
Steal or Forge Kerberos Tickets: Kerberoasting T1558.003 Conti actors use Kerberos attacks to attempt to get the Admin hash.
System Network Configuration Discovery  T1016 Conti ransomware can retrieve the ARP cache from the local system by using the GetIpNetTable() API call and check to ensure IP addresses it connects to are for local, non-internet systems.
System Network Connections Discovery  T1049 Conti ransomware can enumerate routine network connections from a compromised host.
Process Discovery T1057 Conti ransomware can enumerate through all open processes to search for any that have the string sql in their process name.
File and Directory Discovery  T1083 Conti ransomware can discover files on a local system.
Network Share Discovery T1135 Conti ransomware can enumerate remote open server message block (SMB) network shares using NetShareEnum().
Technique Title ID Use
Remote Services: SMB/Windows Admin Shares  T1021.002 Conti ransomware can spread via SMB and encrypts files on different hosts, potentially compromising an entire network.
Taint Shared Content T1080 Conti ransomware can spread itself by infecting other remote machines via network shared drives.
Technique Title ID Use
Data Encrypted for Impact T1486 Conti ransomware can use CreateIoCompletionPort(), PostQueuedCompletionStatus(), and GetQueuedCompletionPort() to rapidly encrypt files, excluding those with the extensions of .exe, .dll, and .lnk. It has used a different AES-256 encryption key per file with a bundled RAS-4096 public encryption key that is unique for each victim. Conti ransomware can use “Windows Restart Manager” to ensure files are unlocked and open for encryption.
Service Stop T1489 Conti ransomware can stop up to 146 Windows services related to security, backup, database, and email solutions through the use of net stop.
Inhibit System Recovery T1490 Conti ransomware can delete Windows Volume Shadow Copies using vssadmin.

Mitigations

CISA, FBI, and NSA recommend that network defenders apply the following mitigations to reduce the risk of compromise by Conti ransomware attacks.

Use multi-factor authentication.

Implement network segmentation and filter traffic.

  • Implement and ensure robust network segmentation between networks and functions to reduce the spread of the ransomware. Define a demilitarized zone that eliminates unregulated communication between networks.
  • Filter network traffic to prohibit ingress and egress communications with known malicious IP addresses. 
  • Enable strong spam filters to prevent phishing emails from reaching end users. Implement a user training program to discourage users from visiting malicious websites or opening malicious attachments. Filter emails containing executable files to prevent them from reaching end users.
  • Implement a URL blocklist and/or allowlist to prevent users from accessing malicious websites.

Scan for vulnerabilities and keep software updated. 

  • Set antivirus/antimalware programs to conduct regular scans of network assets using up-to-date signatures. 
  • Upgrade software and operating systems, applications, and firmware on network assets in a timely manner. Consider using a centralized patch management system. 

Remove unnecessary applications and apply controls.

Implement endpoint and detection response tools. 

  • Endpoint and detection response tools allow a high degree of visibility into the security status of endpoints and can help effectively protect against malicious cyber actors. 

Limit access to resources over the network, especially by restricting RDP. 

  • After assessing risks, if RDP is deemed operationally necessary, restrict the originating sources and require multi-factor authentication.

Secure 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.

Review CISA’s APTs Targeting IT Service Provider Customers guidance for additional mitigations specific to IT Service Providers and their customers.

Use the Ransomware Response Checklist in case of infection.

If a ransomware incident occurs at your organization, CISA, FBI, and NSA recommend the following actions:

CISA, FBI, and NSA strongly discourage paying a ransom to criminal actors. Paying a ransom may embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or may fund illicit activities. Paying the ransom also does not guarantee that a victim’s files will be recovered.

Additional Resources

Free Cyber Hygiene Services

CISA offers a range of no-cost cyber hygiene services to help organizations assess, identify, and reduce their exposure to threats, including ransomware. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate attack vectors.

StopRansomware.gov 

The StopRansomware.gov webpage is an interagency resource that provides guidance on ransomware protection, detection, and response. This includes ransomware alerts, reports, and resources from CISA and other federal partners, including:

Rewards for Justice Reporting

The U.S. Department of State’s Rewards for Justice (RFJ) program offers a reward of up to $10 million for reports of foreign government malicious activity against U.S. critical infrastructure. See the RFJ website for more information and how to report information securely.

Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field-offices, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at [email protected]. When available, please include the following information regarding the incident: date, time, and location of the incident; type of activity; number of people affected; type of equipment used for the activity; the name of the submitting company or organization; and a designated point of contact. If you have any further questions related to this Joint Cybersecurity Advisory, or to request incident response resources or technical assistance related to these threats, contact CISA at [email protected]. For NSA client requirements or general cybersecurity inquiries, contact the NSA Cybersecurity Requirements Center at 410-854-4200 or [email protected].

References

Revisions

September 22, 2021: Initial Version

This product is provided subject to this Notification and this Privacy & Use policy.

Source…

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

This product is provided subject to this Notification and this Privacy & Use policy.

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:

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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

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