CipherWallSelfExtratorDecryptorConsolev15

Hunt Hypothesis

This hypothesis targets the execution of the CipherWall self-extractor decryptor console, a component often associated with ransomware deployment or payload staging that adversaries use to prepare malicious binaries for execution. Proactively hunting for this specific artifact in Azure Sentinel allows the SOC team to identify early-stage ransomware activity or suspicious file operations before the encryption process begins, enabling faster containment and reducing the potential impact on the environment.

YARA Rule

rule CipherWallSelfExtratorDecryptorConsolev15
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 90 61 BE 00 10 42 00 8D BE 00 00 FE FF C7 87 C0 20 02 00 0B 6E 5B 9B 57 83 CD FF EB 0E 90 90 90 90 8A 06 46 88 07 47 01 DB 75 07 8B 1E 83 EE FC 11 DB 72 ED B8 01 00 00 00 01 DB 75 07 8B 1E 83 EE FC 11 DB 11 C0 01 DB 73 EF 75 09 8B 1E 83 EE FC 11 DB 73 E4 }

condition:
		$a0 at pe.entry_point
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: An IT administrator manually executes the CipherWallSelfExtratorDecryptorConsolev15.exe utility from a shared network drive or local temp folder to decrypt a corrupted backup file or restore a specific configuration item outside of the standard automated backup window.

  • Filter/Exclusion: Allow execution if the parent process is explorer.exe or cmd.exe and the user belongs to the BackupAdmins or IT_Ops Active Directory group, provided the file path does not reside in a standard web root or user profile directory.

• Scenario: A scheduled PowerShell task or batch script runs the decryptor console as part of a nightly data retention policy, specifically to decrypt and archive old log files or database dumps before moving them to cold storage.

  • Filter/Exclusion: Exclude executions where the parent process is powershell.exe or cmd.exe and the command line arguments contain specific keywords like -archive, -decrypt, or -retention, or if the task is associated with a known scheduled task ID (e.g., NightlyDataRetention).

• Scenario: A development or QA engineer runs the decryptor tool locally to debug a failed decryption routine or to inspect the internal structure of a test artifact, often launching it directly from a development IDE or a custom script in a user’s home directory.

  • Filter/Exclusion: Allow execution if the user belongs to the DevTeam or QA_Engineers group and the working directory is within a known development share (e.g., \\dev-share\projects\) or the user’s local AppData or Documents folder, excluding cases where the parent process is a browser or mail client.

• Scenario: A service account running a custom application or middleware component invokes the decryptor console to handle on-the-fly decryption of configuration files or secrets