WinZipSelfExtractor22personaleditionWinZipComputing

Hunt Hypothesis

This detection identifies the execution of a specific personal edition self-extractor from WinZip Computing, which adversaries often leverage to stage and deliver secondary payloads during initial access or lateral movement phases. Proactively hunting for this behavior in Azure Sentinel is essential because low-severity detections of legitimate tools can mask malicious activity where attackers abuse trusted software to bypass security controls and establish persistence.

YARA Rule

rule WinZipSelfExtractor22personaleditionWinZipComputing
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 53 FF 15 58 70 40 00 B3 22 38 18 74 03 80 C3 FE 40 33 D2 8A 08 3A CA 74 10 3A CB 74 07 40 8A 08 3A CA 75 F5 38 10 74 01 40 52 50 52 52 FF 15 5C 70 40 00 50 E8 15 FB FF FF 50 FF 15 8C 70 40 00 5B }

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 5 specific false positive scenarios for the WinZipSelfExtractor22personaleditionWinZipComputing detection rule, including recommended filters and exclusions:

• Scenario: IT Helpdesk Deployment of Legacy Software

  • Context: The IT Helpdesk team frequently distributes legacy applications or documentation packs to end-users using a self-extracting .exe archive created with WinZip Personal Edition. This often occurs during onboarding or specific project rollouts where the standard enterprise packaging tool (e.g., SCCM) is unavailable for ad-hoc requests.
  • Filter/Exclusion: Create an exclusion based on the Process Name (winzipse.exe or similar self-extractor name) running under a known Service Account (e.g., DOMAIN\IT-Deploy-Svc) or within specific OU paths designated for “Helpdesk Distribution.”

• Scenario: Scheduled Automated Report Generation

  • Context: A scheduled Task Scheduler job runs nightly to compile audit logs from various departments, compress them into a self-extracting archive using the WinZip Personal Edition engine, and distribute them via email or network share. The rule triggers because the extraction process mimics a user-initiated download of an unknown executable.
  • Filter/Exclusion: Exclude processes where the Parent Process is TaskScheduler.exe (or svchost.exe if running as a service) and the File Path matches a known directory for automated reports (e.g., C:\Reports\Automated\*).

• Scenario: Third-Party Vendor Support Sessions

  • Context: External vendors or consultants connect to the enterprise network via a jump host to troubleshoot issues. They often transfer diagnostic tools or configuration scripts packaged as WinZip self-extractors directly from their local machines to the server for immediate execution, triggering the rule