SEAAXEv22

Hunt Hypothesis

This detection identifies potential malicious activity through the SEAAXEv22 YARA signature, which targets specific file patterns or behaviors indicative of emerging threats within the Azure Sentinel environment. Proactive hunting for this rule is essential to uncover low-severity indicators that may represent early-stage adversary reconnaissance or lateral movement before they escalate into significant incidents.

YARA Rule

rule SEAAXEv22
{
      meta:
		author="malware-lu"
strings:
		$a0 = { FC BC [2] 0E 1F A3 [2] E8 [2] A1 [2] 8B [3] 2B C3 8E C0 B1 03 D3 E3 8B CB BF [2] 8B F7 F3 A5 }

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 3-5 specific false positive scenarios for the SEAAXEv22 detection rule, formatted as requested:

• Scenario: Legitimate execution of Microsoft Office Click-to-Run updates.

  • Context: The OfficeClickToRun.exe process frequently launches child processes or modifies registry keys in a way that matches the SEAAX signature logic (often involving temporary file creation and network calls). This is common during scheduled maintenance windows on workstations.
  • Filter/Exclusion: Add an exclusion for the parent process path C:\Program Files\Microsoft Office Client\OfficeClickToRun.exe or filter out events where the command line contains /update.

• Scenario: Scheduled antivirus definition updates via Symantec Endpoint Protection (SEP) or CrowdStrike Falcon.

  • Context: During off-hours, the endpoint protection agent runs a scheduled job to download and install new threat definitions. These agents often spawn helper processes that execute scripts or modify system files, triggering the YARA rule’s heuristics for potential malicious activity.
  • Filter/Exclusion: Create an exclusion based on the process name Symantec Endpoint Protection (or ccSetCfg.exe) and Falcon Sensor Service, specifically excluding events occurring between 02:00 and 04:00 local time.

• Scenario: Deployment of enterprise-wide patches via Microsoft System Center Configuration Manager (SCCM) or Intune.

  • Context: When SCCM pushes a cumulative update to the fleet, it executes PowerShell scripts that invoke msiexec.exe or wusa.exe. These installation processes often generate temporary artifacts and network traffic patterns that mimic the behavior detected by SEAAXEv22.
  • Filter/Exclusion: Exclude events where the parent process is ccmsetup.exe (SCCM) or `Intune