SixtoFourv10

Hunt Hypothesis

This detection identifies potential malicious activity by matching file artifacts against the specific patterns defined in the SixtoFourv10 YARA signature within Azure Sentinel logs. Proactive hunting for this indicator is essential to uncover stealthy threats that may evade standard alerting thresholds, allowing the SOC team to validate low-severity signals before they escalate into broader incidents.

YARA Rule

rule SixtoFourv10
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 50 55 4C 50 83 [2] FC BF [2] BE [2] B5 ?? 57 F3 A5 C3 33 ED }

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

Here are 4 specific false positive scenarios for the SixtoFourv10 detection rule, including recommended filters and exclusions tailored for an enterprise environment:

• Scenario: Automated Endpoint Security Scans

  • Context: The YARA rule likely detects a specific memory pattern or file signature associated with SixtoFour. Enterprise endpoint protection suites (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) frequently spawn child processes to perform real-time scanning or scheduled deep scans, which may temporarily instantiate the exact binary structure flagged by the rule.
  • Filter/Exclusion: Create a whitelist exclusion based on the parent process name and path. Exclude any instance where the parent process is C:\Program Files\CrowdStrike\csagent.exe or C:\Windows\System32\DPSvc.exe, provided the triggered file resides within the vendor’s installation directory (e.g., C:\ProgramData\McAfee\).

• Scenario: Scheduled Patch Deployment via SCCM

  • Context: During nightly maintenance windows, Microsoft Endpoint Configuration Manager (SCCM) or Ivanti Neurons executes scheduled deployment tasks. These agents often extract temporary installer packages containing the SixtoFour component to apply updates, triggering a match on the extracted executable before it is fully integrated into the OS.
  • Filter/Exclusion: Implement a time-based exclusion window (e.g., 02:00 – 06:00 local time) for alerts generated by processes running under the SYSTEM or Network Service account where the file path contains \Temp\ or \SoftwareDistribution\.

• Scenario: Legacy Application Backup Routines

  • Context: Many enterprises utilize legacy backup solutions like Veeam Agent or Commvault that run scheduled jobs to archive application data. These tools often invoke