The hypothesis is that the detection of the 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_wmi_Implant {
meta:
description = "Detects EquationGroup Tool - April Leak"
author = "Florian Roth"
reference = "https://steemit.com/shadowbrokers/@theshadowbrokers/lost-in-translation"
date = "2017-04-15"
hash1 = "de08d6c382faaae2b4b41b448b26d82d04a8f25375c712c12013cb0fac3bc704"
strings:
$x1 = "SELECT ProcessId,Description,ExecutablePath FROM Win32_Process" fullword ascii
condition:
( uint16(0) == 0x5a4d and filesize < 50KB and all of them )
}
This YARA rule can be deployed in the following contexts:
This rule contains 1 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Task
Description: A legitimate system maintenance task, such as schtasks.exe running a scheduled job to clean temporary files or update system settings.
Filter/Exclusion: Exclude processes associated with schtasks.exe where the command line includes known maintenance scripts (e.g., cleanmgr.exe, diskcleanup.exe).
Scenario: Admin Performing Disk Cleanup
Description: An administrator using diskcleanup.exe to remove temporary files or system cache.
Filter/Exclusion: Exclude processes where the command line includes diskcleanup.exe and the user is a domain admin or has elevated privileges.
Scenario: Antivirus Scan Using ClamAV
Description: A legitimate antivirus scan initiated by ClamAV, which may trigger similar file or process detections.
Filter/Exclusion: Exclude processes with clamscan.exe or clamav in the command line, especially when running in safe mode or during scheduled scans.
Scenario: Log File Compression by Windows Task Scheduler
Description: A scheduled task using compact.exe to compress log files, which may resemble the behavior of malicious tools.
Filter/Exclusion: Exclude processes where compact.exe is used with parameters like /compact or /d to compress log directories.
Scenario: Software Update Deployment via SCCM
Description: A Software Center or SCCM (System Center Configuration Manager) update deployment that executes scripts or tools similar to the EquationGroup tool.
Filter/Exclusion: Exclude processes initiated by ccmexec.exe or setup.exe associated with SCCM update deployments.