|Platform||Linux, macOS, Windows|
|Data Sources||API monitoring, Process monitoring, File monitoring|
An adversary can leverage a computer's peripheral devices (e.g., microphones and webcams) or applications (e.g., voice and video call services) to capture audio recordings for the purpose of listening into sensitive conversations to gather information.
Malware or scripts may be used to interact with the devices through an available API provided by the operating system or an application to capture audio. Audio files may be written to disk and exfiltrated later.
- EvilGrab has the capability to capture audio from a victim machine.1
- Flame can record audio using any existing hardware recording devices.2
- Janicab captured audio and sent it out to a C2 server 3.
- T9000 uses the Skype API to record audio and video calls. It writes encrypted data to
Mitigating this technique specifically may be difficult as it requires fine-grained API control. Efforts should be focused on preventing unwanted or unknown code from executing on a system.
Detection of this technique may be difficult due to the various APIs that may be used. Telemetry data regarding API use may not be useful depending on how a system is normally used, but may provide context to other potentially malicious activity occurring on a system.
Behavior that could indicate technique use include an unknown or unusual process accessing APIs associated with devices or software that interact with the microphone, recording devices, or recording software, and a process periodically writing files to disk that contain audio data.
- PwC and BAE Systems. (2017, April). Operation Cloud Hopper: Technical Annex. Retrieved April 13, 2017.
- Gostev, A. (2012, May 30). Flame: Bunny, Frog, Munch and BeetleJuice…. Retrieved March 1, 2017.
- Brod. (2013, July 15). Signed Mac Malware Using Right-to-Left Override Trick. Retrieved July 17, 2017.
- Grunzweig, J. and Miller-Osborn, J.. (2016, February 4). T9000: Advanced Modular Backdoor Uses Complex Anti-Analysis Techniques. Retrieved April 15, 2016.
- Beechey, J. (2010, December). Application Whitelisting: Panacea or Propaganda?. Retrieved November 18, 2014.
- Tomonaga, S. (2016, January 26). Windows Commands Abused by Attackers. Retrieved February 2, 2016.
- NSA Information Assurance Directorate. (2014, August). Application Whitelisting Using Microsoft AppLocker. Retrieved March 31, 2016.
- Corio, C., & Sayana, D. P. (2008, June). Application Lockdown with Software Restriction Policies. Retrieved November 18, 2014.
- Microsoft. (2012, June 27). Using Software Restriction Policies and AppLocker Policies. Retrieved April 7, 2016.