md5 24f2df1b9d49cfb02d8954b08dba471f

Hunt Hypothesis

The detection rule identifies potential malicious activity associated with the MD5 hash 24f2df1b9d49cfb02d8954b08dba471f, which may indicate the presence of known or emerging threats. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate potential compromise early, especially given the low severity threshold which may mask more sophisticated attacks.

YARA Rule

rule md5_24f2df1b9d49cfb02d8954b08dba471f {
    strings: $ = "))unlink('../media/catalog/category/'.basename($"
    condition: any of them
}

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
• Source Rule

False Positive Guidance

• Scenario: Legitimate software update using msiexec.exe
  Filter/Exclusion: Check for msiexec.exe with command line arguments containing /i (install) and a known valid MSI file hash.
  Example Filter: process.exe == "msiexec.exe" and process.args contains "/i" and file.hash.md5 == "known_valid_hash"

• Scenario: Scheduled system backup using wbadmin.exe
  Filter/Exclusion: Filter events where wbadmin.exe is executed with the /backup flag and the backup path is a known system directory (e.g., C:\Windows\Temp).
  Example Filter: process.exe == "wbadmin.exe" and process.args contains "/backup" and process.cwd contains "C:\Windows\Temp"

• Scenario: Antivirus signature update using msmpeng.exe
  Filter/Exclusion: Exclude processes initiated by msmpeng.exe that are part of a scheduled Microsoft Defender signature update.
  Example Filter: process.exe == "msmpeng.exe" and process.parent.exe == "svchost.exe" and process.parent.args contains "RpcSs"

• Scenario: Log file parsing using logparser.exe
  Filter/Exclusion: Exclude instances where logparser.exe is used to parse system or application logs (e.g., C:\Windows\System32\logfiles).
  Example Filter: process.exe == "logparser.exe" and process.args contains "C:\\Windows\\System32\\logfiles"

• Scenario: Disk imaging using dd.exe or robocopy.exe
  Filter/Exclusion: Exclude processes where dd.exe or robocopy.exe is used for legitimate disk imaging or data migration tasks.
  Example Filter: `process.exe in (”