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NullsoftPIMPInstallSystemv1x

yara LOW Yara-Rules
community
This rule was pulled from an open-source repository and enriched with AI. Validate in a test environment before deploying to production.
View original rule at Yara-Rules →
Retrieved: 2026-08-24T23:00:00Z · Confidence: medium

Hunt Hypothesis

This hunt hypothesis investigates the execution of the Nullsoft PIMP installer system to identify potential supply chain compromises or unauthorized software deployments that may serve as a precursor for lateral movement. Proactively hunting for this behavior in Azure Sentinel is essential because low-severity installers are frequently overlooked by adversaries, allowing them to establish persistent footholds before triggering higher-level alerts.

YARA Rule

rule NullsoftPIMPInstallSystemv1x
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 83 EC 5C 53 55 56 57 FF 15 [3] 00 }

condition:
		$a0 at pe.entry_point
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

This rule contains 1 string patterns in its detection logic.

False Positive Guidance

Here are 5 specific false positive scenarios for the NullsoftPIMPInstallSystemv1x detection rule, along with targeted filters and exclusions:

Original source: https://github.com/Yara-Rules/rules/blob/main/packers/packer.yar