md5 71a7c769e644d8cf3cf32419239212c7

Hunt Hypothesis

The hypothesis is that the detected MD5 hash corresponds to a malicious file used in initial compromise or persistence, indicating potential adversary activity. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage threats before they escalate.

YARA Rule

rule md5_71a7c769e644d8cf3cf32419239212c7 {
	/*
    // $GLOBALS['ywanc2']($GLOBALS['ggbdg61']
    */
    strings: $ = /\$GLOBALS\['[\w\d]+'\]\(\$GLOBALS\['[\w\d]+'\]/
    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 system update via Windows Update
  Filter/Exclusion: Check for ProcessName containing wuauclt.exe or svchost.exe with CommandLine indicating Windows Update tasks.
  Example Filter: ProcessName in ("wuauclt.exe", "svchost.exe") and CommandLine contains "wuauclt.exe"

• Scenario: Scheduled backup job using Veeam Backup & Replication
  Filter/Exclusion: Filter by ProcessName containing veeambackup.exe or Veeam.Backup.exe and check for CommandLine with backup-related arguments.
  Example Filter: ProcessName contains "veeambackup.exe"

• Scenario: Antivirus signature update via Microsoft Defender
  Filter/Exclusion: Look for ProcessName as MsMpEng.exe and check for CommandLine containing MpCmdRun.exe with /SignatureUpdate or /Update arguments.
  Example Filter: ProcessName contains "MsMpEng.exe" and CommandLine contains "MpCmdRun.exe"

• Scenario: Log file parsing or analysis by Splunk
  Filter/Exclusion: Identify processes with ProcessName containing splunkd.exe or splunkforwarder.exe and filter by CommandLine involving log processing.
  Example Filter: ProcessName contains "splunkd.exe" and CommandLine contains "log" or "parse"

• Scenario: Network traffic analysis using Wireshark
  Filter/Exclusion: Filter for ProcessName containing wireshark.exe or tshark.exe and check for CommandLine involving capture or analysis commands.
  Example Filter: ProcessName contains "wireshark.exe" and CommandLine contains "capture" or "analyze"