Ezcob

Hunt Hypothesis

The Ezcob rule detects potential adversary behavior involving the use of a custom or obfuscated command-line interface to execute arbitrary code, which may indicate a low-severity persistence or initial access tactic. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage threats that could evolve into more sophisticated attacks.

YARA Rule

rule Ezcob : Family
{
    meta:
        description = "Ezcob"
        author = "Seth Hardy"
        last_modified = "2014-06-23"
        
    condition:
        EzcobStrings
}

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
• Source Rule

False Positive Guidance

• Scenario: Scheduled system backup using Veeam Backup & Replication
  Filter/Exclusion: process.name != "vbm.exe" or process.parent.name != "vbm.exe"

• Scenario: Administrative task to update Microsoft SQL Server via SQL Agent Job
  Filter/Exclusion: process.name != "sqlservr.exe" or process.parent.name != "sqlservr.exe"

• Scenario: Regular Windows Update installation triggered by Windows Task Scheduler
  Filter/Exclusion: process.name != "wuauclt.exe" or process.parent.name != "svchost.exe"

• Scenario: Docker container startup or management via Docker Desktop
  Filter/Exclusion: process.name != "dockerd.exe" or process.parent.name != "dockerd.exe"

• Scenario: Ansible playbook execution for configuration management
  Filter/Exclusion: process.name != "ansible.exe" or process.parent.name != "ansible.exe"