Cross-source coverage

T1027.003 / ATT&CK

Obfuscated Files or Information: Steganography

5 rules across 1 source.

From MITRE ATT&CK 19.2

Adversaries may use steganography techniques in order to prevent the detection of hidden information. Steganographic techniques can be used to hide data in digital media such as images, audio tracks, video clips, or text files.

Duqu was an early example of malware that used steganography. It encrypted the gathered information from a victim's system and hid it within an image before exfiltrating the image to a C2 server.

By the end of 2017, a threat group used Invoke-PSImage to hide PowerShell commands in an image file (.png) and execute the code on a victim's system. In this particular case the PowerShell code downloaded another obfuscated script to gather intelligence from the victim's machine and communicate it back to the adversary.

Tactics
Stealth
Platforms
Linux · macOS · Windows
Telemetry
WinEventLog:SysmonWinEventLog:Securityauditd:SYSCALLmacos:osquerymacos:unifiedlog

How MITRE says to detect it DET0119

Detection Strategy for Steganographic Abuse in File & Script Execution

Windows Analytic 0331

Detects execution of image viewers or PowerShell scripts accessing or decoding files with mismatched MIME headers or embedded script-like byte patterns; often correlated with suspicious parent-child process lineage and outbound connections.

  • WinEventLog:Sysmon EventCode=1
  • WinEventLog:Sysmon EventCode=3, 22
  • WinEventLog:Security EventCode=4663, 4670, 4656

Linux Analytic 0332

Detects access to media files followed by execution of scripts (bash, Python, etc.) referencing those same files, or outbound traffic triggered shortly after file read. Correlates unusual use of tools like `steghide`, `exiftool`, or image libraries.

  • auditd:SYSCALL open
  • auditd:SYSCALL execve
  • auditd:SYSCALL connect

macOS Analytic 0333

Detects manipulation of PNG, JPG, or GIF files by user-initiated scripts followed by script execution or exfiltration behavior, especially from `osascript`, `python`, or `bash`, in combination with LaunchAgent persistence or curl activity.

  • macos:osquery file_events
  • macos:osquery process_events
  • macos:unifiedlog network connection events

SigmaHQ/sigma

5 rules
Detection Severity Format
Findstr Launching .lnk File Medium Sigma
Steganography Extract Files with Steghide Low Sigma
Steganography Hide Files with Steghide Low Sigma
Steganography Hide Zip Information in Picture File Low Sigma
Steganography Unzip Hidden Information From Picture File Low Sigma

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