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Detects a relatively small Java class file obfuscated by Allatori Obfuscator

yara MEDIUM signature-base
florian-roth
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 signature-base →
Retrieved: 2026-08-06T23:00:00Z · Confidence: medium

Hunt Hypothesis

This hunt hypothesis targets adversaries who deploy compact, Allatori-obfuscated Java classes to conceal malicious logic and evade static analysis within cloud-native environments. A proactive search in Azure Sentinel is essential because obfuscation often masks advanced persistent threats that traditional signature-based detections might overlook due to the file’s small size and complex structure.

YARA Rule

rule SUSP_JAVA_Class_Allatori_Obfuscator_Aug25 {
   meta:
      description = "Detects a relatively small Java class file obfuscated by Allatori Obfuscator"
      author = "Florian Roth"
      reference = "https://www.malwation.com/blog/technical-analysis-of-a-stealth-java-loader-used-in-phishing-campaigns-targeting-turkiye"
      date = "2025-08-07"
      score = 50
      hash1 = "0a7fddd91b332c8daee2c0727b884fc92cfaede02883dbad75f7efc299e884e3"
      id = "d179c944-90c6-5519-8ca2-6450561a31da"
   strings:
      $x1 = "Obfuscation by Allatori Obfuscator" ascii fullword
   condition:
      uint16(0) == 0x4b50
      and filesize < 500KB
      and $x1
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

This rule contains 1 string patterns in its detection logic.

References

False Positive Guidance

Here are 5 specific false positive scenarios for the rule “Detects a relatively small Java class file obfuscated by Allatori Obfuscator,” including suggested filters and exclusions:

Original source: https://github.com/Neo23x0/signature-base/blob/main/yara/mal_soupdealer_java_aug25.yar