Equation Group hack tool set

Hunt Hypothesis

The Equation Group hack tool set is associated with advanced persistent threats and may indicate the presence of sophisticated malware or espionage activity. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential long-term compromise and mitigate advanced threats before they cause significant damage.

YARA Rule

rule EquationGroup_watcher_solaris_i386_v_3_3_0 {
   meta:
      description = "Equation Group hack tool set"
      author = "Florian Roth"
      reference = "https://medium.com/@shadowbrokerss/dont-forget-your-base-867d304a94b1"
      date = "2017-04-09"
      hash1 = "395ec2531970950ffafde234dded0cce0c95f1f9a22763d1d04caa060a5222bb"
   strings:
      $s1 = "getexecname" fullword ascii
      $s2 = "invalid option `" fullword ascii
      $s6 = "__fpstart" fullword ascii
      $s12 = "GHFIJKLMNOPQRSTUVXW" fullword ascii
   condition:
      ( uint16(0) == 0x457f and filesize < 700KB and all of them )
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

Microsoft Defender for Endpoint — Custom indicators / advanced hunting
Email Gateway — Attachment scanning
File Share Monitoring — Periodic scanning of shared drives
YARA CLI — Manual threat hunting on endpoints

This rule contains 4 string patterns in its detection logic.

References

False Positive Guidance

Scenario: Legitimate System Maintenance Task
Description: A system administrator is running a scheduled maintenance job that uses the equation_group_tool.exe as part of a known enterprise toolset for system diagnostics.
Filter/Exclusion: Exclude processes associated with the enterprise toolset (e.g., equation_group_tool.exe where process.parent_process_name = "enterprise_diag_scheduler.exe")
Scenario: Scheduled Job for Log Analysis
Description: A scheduled job runs a script that uses the equation_group_tool.exe to parse and analyze system logs as part of a regular log management process.
Filter/Exclusion: Exclude processes where process.file_name = "equation_group_tool.exe" and process.command_line contains "log_analysis" or process.parent_process_name = "log_analyzer_service.exe"
Scenario: Admin Task for Network Monitoring
Description: An administrator is using the equation_group_tool.exe to monitor network traffic as part of a legitimate network monitoring tool.
Filter/Exclusion: Exclude processes where process.file_name = "equation_group_tool.exe" and process.parent_process_name = "network_monitor_service.exe" or process.command_line contains "network_monitor"
Scenario: Software Update Deployment
Description: A software update package includes the equation_group_tool.exe as part of a deployment script, which is executed during a routine patching process.
Filter/Exclusion: Exclude processes where process.file_name = "equation_group_tool.exe" and process.parent_process_name = "patching_service.exe" or process.command_line contains "patch"
Scenario: Custom Script for Data Extraction
Description: A custom script written by the internal security team uses the equation_group_tool.exe to extract data from a database for compliance reporting.
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