ASProtectv20

Hunt Hypothesis

This detection identifies potential malicious activity where adversaries utilize the ASProtectv20 protection mechanism to obfuscate their payloads and evade standard signature-based defenses within the Azure Sentinel environment. Proactive hunting for this behavior is essential because low-severity alerts often indicate early-stage reconnaissance or stealthy persistence attempts that could escalate into significant threats if not investigated before they establish a foothold.

YARA Rule

rule ASProtectv20
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 68 01 ?? 40 00 E8 01 00 00 00 C3 C3 }

condition:
		$a0
}

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 5 specific false positive scenarios for the ASProtectv20 detection rule, including suggested filters and exclusions tailored for an enterprise environment:

• Scenario: Deployment of Licensed Software via Endpoint Management Tools

  • Context: Enterprise software deployment tools (e.g., Microsoft Intune, SCCM, or Ivanti) often push updates or new applications that utilize ASProtect for license validation. When these agents install the software package on a workstation, the YARA rule triggers because the installer executable contains the ASProtect signature.
  • Suggested Filter/Exclusion: Exclude processes originating from known deployment engines. Add an exclusion for msiexec.exe, ccmsetup.exe (SCCM), and IntuneManagementExtension.exe when they are running under the context of a software installation job, specifically targeting file paths within the C:\Program Files\Microsoft Intune Agent\ or C:\Windows\CCM\ directories.

• Scenario: Execution of Scheduled Backup Verification Jobs

  • Context: Many enterprise backup solutions (e.g., Veeam, Acronis Cyber Protect) include a “License Check” or “Integrity Scan” scheduled task that runs daily at 02:00 AM. This utility often invokes an ASProtect-protected module to verify the validity of the backup server’s license before initiating the job, triggering the rule during off-hours.
  • Suggested Filter/Exclusion: Implement a time-based exclusion or process-specific filter for vssvc.exe and AcronisCyberAgent.exe. Configure the detection logic to suppress alerts if the event occurs between 01:00 and 04:00 on weekdays, provided the user context is SYSTEM or a dedicated service account (e.g., DOMAIN\BackupSvc).

• **Scenario: Administrative Review of Protected Financial