Critical Remote Hacking Flaws Disclosed in Linphone and MicroSIP Softphones

October 14, 2021Ravie Lakshmanan

Multiple security vulnerabilities have been disclosed in softphone software from Linphone and MicroSIP that could be exploited by an unauthenticated remote adversary to crash the client and even extract sensitive information like password hashes by simply making a malicious call. The vulnerabilities, which were discovered by Moritz Abrell of German pen-testing firm SySS GmbH, have since been addressed by the respective manufacturers following responsible disclosure. Softphones are essentially software-based phones that mimic desk phones and allow for making telephone calls over the Internet without the need for using dedicated hardware. At the core of the issues are the SIP services offered by the clients to connect two peers to facilitate telephony services in IP-based mobile networks. SIP aka Session Initiation Protocol is a  signaling protocol  that’s used to control interactive communication sessions, such as voice, video, chat and instant messaging, as well as games and v