T5000

Hunt Hypothesis

This hypothesis posits that adversaries are establishing persistent footholds by leveraging standard administrative activities to evade initial detection thresholds within Azure Sentinel. Proactive hunting for this behavior is critical to identify subtle deviations in baseline operations before they escalate into significant security incidents.

YARA Rule

rule T5000 : Family
{
    meta:
        description = "T5000"
        author = "Seth Hardy"
        last_modified = "2014-06-26"
        
    condition:
        T5000Strings
}

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

Here are 4 specific false positive scenarios for the T5000 detection rule in an enterprise environment, including suggested filters and exclusions:

• Scenario: Automated Patch Deployment via Configuration Management Tools

  • Context: Scheduled nightly jobs run by tools like Ansible, Chef, or SCCM (System Center Configuration Manager) that push security updates to thousands of endpoints. These agents often execute commands with elevated privileges, mimicking suspicious administrative activity across multiple hosts simultaneously.
  • Filter/Exclusion: Create an exclusion rule based on the Source User Account and Process Name. Whitelist accounts named Ansible-Service, SCCM-Agent, or Chef-Client running processes like ansible-playbook.exe or ccmexec.exe. Additionally, filter by a specific time window (e.g., 02:00–04:00 UTC) to cover maintenance windows.

• Scenario: Enterprise Backup and Snapshot Operations

  • Context: High-volume backup solutions such as Veeam Backup & Replication, Commvault, or AWS Backup perform frequent file system scans, temporary file creation, and volume shadowing. These operations generate massive amounts of I/O and process execution events that can be misinterpreted as unauthorized data access or lateral movement.
  • Filter/Exclusion: Exclude traffic originating from known backup service accounts (e.g., svc-veeam-backup, commvault-agent) targeting specific backup storage paths (e.g., \\BackupServer\Share). Implement a filter that ignores events where the Destination Path contains keywords like _backup_, .vbk, or .snapshot and the process image hash matches the known vendor signature.

• Scenario: Software Distribution via Endpoint Management Platforms

  • Context: Tools like Microsoft Intune, **Jam