Imminent

Hunt Hypothesis

This detection identifies potential early-stage adversary activity by leveraging a specific YARA signature to scan for known malicious patterns within the Azure Sentinel environment. Proactive hunting is essential because this low-severity indicator may represent novel threats that require manual investigation before they escalate into more critical incidents.

YARA Rule

rule Imminent : RAT
{
    meta:
        author = " Kevin Breen <kevin@techanarchy.net>"
        date = "2014/04"
        ref = "http://malwareconfig.com/stats/Imminent"
        maltype = "Remote Access Trojan"
        filetype = "exe"

    strings:
        $v1a = "DecodeProductKey"
        $v1b = "StartHTTPFlood"
        $v1c = "CodeKey"
        $v1d = "MESSAGEBOX"
        $v1e = "GetFilezillaPasswords"
        $v1f = "DataIn"
        $v1g = "UDPzSockets"
        $v1h = {52 00 54 00 5F 00 52 00 43 00 44 00 41 00 54 00 41}

        $v2a = "<URL>k__BackingField"
        $v2b = "<RunHidden>k__BackingField"
        $v2c = "DownloadAndExecute"
        $v2d = "-CHECK & PING -n 2 127.0.0.1 & EXIT" wide
        $v2e = "england.png" wide
        $v2f = "Showed Messagebox" wide
    condition:
        all of ($v1*) or all of ($v2*)
}

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 14 string patterns in its detection logic.

• Source Rule

False Positive Guidance

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

• Scheduled Endpoint Protection Scans

  • Scenario: The Imminent YARA rule may flag the legitimate execution of signature updates and heuristic scans performed by major EDR agents (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or SentinelOne) during their configured maintenance windows. These processes often spawn child processes with similar memory signatures to those targeted by the rule.
  • Filter/Exclusion: Exclude process paths containing known vendor directories (e.g., C:\Program Files\CrowdStrike\*, C:\ProgramData\Microsoft\Windows Defender\*) and filter out events occurring strictly between 02:00–04:00 local time on weekdays.

• Software Deployment via Configuration Management

  • Scenario: Automated patch management or application deployment tools like Ansible, SCCM (Microsoft Endpoint Configuration Manager), or Chef frequently execute scripts that download, unpack, and install software packages. These actions involve creating temporary executables and modifying system files, which can mimic the behavior patterns Imminent is designed to catch.
  • Filter/Exclusion: Create a whitelist for process names associated with deployment agents (e.g., ccmexec.exe, Ansible-Runner, chef-client) and exclude file paths located in temporary staging directories such as %TEMP%\SCCM\ or /var/tmp/chef.

• Administrative Backup Operations

  • Scenario: Enterprise backup solutions like Veeam Backup & Replication, Commvault, or Acronis Cyber Protect often run scheduled jobs that involve heavy file I/O and the execution of proprietary agents to verify data integrity. The Imminent rule might interpret the rapid creation and modification of large backup archives