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Detects EquationGroup Tool - April Leak

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: 2026-06-08T23:00:01Z · Confidence: medium

Hunt Hypothesis

The hypothesis is that the detection of EquationGroup Tool - April Leak indicates potential adversary use of sophisticated, legacy malware associated with advanced persistent threats. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate long-term, stealthy threats that may have evaded traditional detection mechanisms.

YARA Rule

rule EquationGroup_Toolset_Apr17_Doublepulsar_1_3_1 {
   meta:
      description = "Detects EquationGroup Tool - April Leak"
      author = "Florian Roth"
      reference = "https://steemit.com/shadowbrokers/@theshadowbrokers/lost-in-translation"
      date = "2017-04-15"
      hash1 = "15ffbb8d382cd2ff7b0bd4c87a7c0bffd1541c2fe86865af445123bc0b770d13"
   strings:
      $x1 = "[+] Ping returned Target architecture: %s - XOR Key: 0x%08X" fullword ascii
      $x2 = "[.] Sending shellcode to inject DLL" fullword ascii
      $x3 = "[-] Error setting ShellcodeFile name" fullword ascii
   condition:
      ( uint16(0) == 0x5a4d and filesize < 100KB and 1 of them )
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

This rule contains 3 string patterns in its detection logic.

References

False Positive Guidance

Original source: https://github.com/Yara-Rules/rules/blob/main/malware/APT_eqgrp_apr17.yar