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XObject's require v1.4+

yara LOW Yara-Rules
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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: 2026-05-12T23:00:00Z · Confidence: medium

Hunt Hypothesis

The detection identifies potential use of outdated or unsupported XObject libraries, which may indicate the presence of legacy or malicious code attempting to exploit known vulnerabilities. SOC teams should proactively hunt for this behavior to identify and mitigate potential attack vectors that could leverage outdated dependencies in their Azure Sentinel environment.

YARA Rule

rule invalid_XObject_js : PDF raw
{
	meta:
		author = "Glenn Edwards (@hiddenillusion)"
		description = "XObject's require v1.4+"
		ref = "https://blogs.adobe.com/ReferenceXObjects/"
		version = "0.1"
		weight = 2
		
	strings:
		$magic = { 25 50 44 46 }
		$ver = /%PDF-1\.[4-9]/
		
		$attrib0 = /\/XObject/
		$attrib1 = /\/JavaScript/
		
	condition:
		$magic in (0..1024) and not $ver and all of ($attrib*)
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

This rule contains 4 string patterns in its detection logic.

False Positive Guidance

Original source: https://github.com/Yara-Rules/rules/blob/main/maldocs/Maldoc_PDF.yar