The hypothesis is that the detection of EquationGroup Tool - April Leak indicates potential adversary activity leveraging stolen malware components to execute persistent, stealthy attacks within the network. A SOC team should proactively hunt for this behavior in Azure Sentinel to identify and mitigate advanced threats that may have already established a foothold in the environment.
YARA Rule
rule EquationGroup_Toolset_Apr17_Shares_Target {
meta:
description = "Detects EquationGroup Tool - April Leak"
author = "Florian Roth"
reference = "https://steemit.com/shadowbrokers/@theshadowbrokers/lost-in-translation"
date = "2017-04-15"
hash1 = "6c57fb33c5e7d2dee415ae6168c9c3e0decca41ffe023ff13056ff37609235cb"
strings:
$s1 = "Select * from Win32_Share" fullword ascii
$s2 = "slocalhost" fullword wide
$s3 = "\\\\%ls\\root\\cimv2" fullword wide
$s4 = "\\\\%ls\\%ls" fullword ascii
condition:
( uint16(0) == 0x5a4d and filesize < 200KB and all of them )
}
This YARA rule can be deployed in the following contexts:
This rule contains 4 string patterns in its detection logic.
Scenario: Scheduled System Maintenance Task
Description: A legitimate scheduled task running a script or tool like PowerShell.exe or task scheduler that performs routine system maintenance.
Filter/Exclusion: Check for ProcessName containing PowerShell or taskhost.exe and filter out tasks with known maintenance scripts or paths like C:\Windows\System32\tasks\.
Scenario: Software Update Deployment
Description: A tool like Windows Update or Chocolatey running an update or installation process that mimics the behavior of the EquationGroup tool.
Filter/Exclusion: Filter out processes with ProcessName like wuauclt.exe or choco.exe, or check for CommandLine containing update or install.
Scenario: Admin Debugging Session
Description: A system administrator using Process Explorer or Procmon to debug or analyze processes, which may trigger similar behavior to the EquationGroup tool.
Filter/Exclusion: Exclude processes with ProcessName like procexp.exe or procmon.exe, or filter based on user context (e.g., User field is Administrator).
Scenario: Legitimate Malware Analysis Environment
Description: A sandbox or analysis environment running the EquationGroup tool for forensic analysis, which may trigger the rule.
Filter/Exclusion: Check for Machine or Hostname containing keywords like sandbox, analysis, or vm, or filter based on SourceIP from known analysis labs.
Scenario: Network Monitoring Tool Execution
Description: A network monitoring tool like Wireshark or tcpdump running in the background and generating similar network activity to the EquationGroup tool.
Filter/Exclusion: Exclude processes with `ProcessName