The hypothesis is that the detection of EquationGroup Tool - April Leak indicates potential adversary use of legacy malware with known persistence mechanisms. A SOC team should proactively hunt for this behavior in Azure Sentinel to identify and mitigate long-term threats that may have evaded traditional detection methods.
YARA Rule
rule EquationGroup_Toolset_Apr17_PC_LP {
meta:
description = "Detects EquationGroup Tool - April Leak"
author = "Florian Roth"
reference = "https://steemit.com/shadowbrokers/@theshadowbrokers/lost-in-translation"
date = "2017-04-15"
hash1 = "3a505c39acd48a258f4ab7902629e5e2efa8a2120a4148511fe3256c37967296"
strings:
$s1 = "* Failed to get connection information. Aborting launcher!" fullword wide
$s2 = "Format: <command> <target port> [lp port]" fullword wide
condition:
( uint16(0) == 0x5a4d and filesize < 200KB and all of them )
}
This YARA rule can be deployed in the following contexts:
This rule contains 2 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Task
Description: A legitimate system maintenance task, such as schtasks.exe running a cleanup job, may trigger the rule due to similar process names or behavior.
Filter/Exclusion: Exclude processes initiated by schtasks.exe with known maintenance job names (e.g., Cleanup-System-Logs or DiskDefrag).
Scenario: Microsoft Equation Editor Usage
Description: The EquationGroup tool may be confused with the Microsoft Equation Editor (eqnedit.exe), which is used in some enterprise environments for document formatting.
Filter/Exclusion: Exclude processes with the full path C:\Windows\System32\eqnedit.exe or processes initiated by mspaint.exe or wordpad.exe.
Scenario: Admin User Performing File Integrity Check
Description: An admin user may be using tools like PowerShell.exe or certutil.exe to verify file integrity or check system files, which could resemble malicious activity.
Filter/Exclusion: Exclude processes initiated by users with the Administrators group and running from trusted locations (e.g., C:\Windows\System32\ or C:\Windows\Temp\).
Scenario: Legacy Antivirus Scan
Description: Some legacy antivirus tools, such as avgnt.exe or mcafee.exe, may perform file scanning that could trigger the rule due to similar process behavior.
Filter/Exclusion: Exclude processes with known antivirus vendor names or running from their respective installation directories (e.g., C:\Program Files\AVG\ or C:\Program Files\McAfee\).
Scenario: Windows Update or Patching Job
Description: Windows Update or patching jobs, initiated by wusa.exe or `d