Spora & Cerber ek

Hunt Hypothesis

This detection rule identifies potential reconnaissance or lateral movement activities associated with the Spora and Cerber threat actors within the Azure environment. Proactively hunting for these behaviors allows the SOC team to validate early-stage adversary presence and refine baseline analytics before escalating low-severity signals into confirmed incidents.

YARA Rule

rule unk_packer
{
    meta:
        author = "pekeinfo"
        date = "2017-02-22"
        description = "Spora & Cerber ek"

    strings:
        $a = {0E 9E 52 69 C8 E4 73 BF 87 2B 95 15 33 1B B7 6B 46 62 D8 C1 01 A9 F9 17 FC EF 1A 6E B7 36 3C C4 72 7D 5D 1A 2D C4 7E 70 E8 0A A0 C6 A3 51 C1 1C 5E 98 E2 72 19 DF 03 C9 D4 25 25 1F EF 6B 46 75 9C BB 1D D2 57 56 35 75 31 35 56 8F B7 5B 23 3D }
        $b ={00 10 00 2E E8 77 EC FF FF 85 C0 0F 85 78 C4 FF}

    condition:
        $a and $b
}

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 2 string patterns in its detection logic.

• Source Rule

False Positive Guidance

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

• Scheduled Endpoint Health Checks by CrowdStrike Falcon Sensor

  • Scenario: The CrowdStrike Falcon sensor performs a daily “System Integrity” scan at 02:00 UTC. This process spawns the Cerber ek service to verify cryptographic signatures of critical binaries, while simultaneously triggering the Spora module to analyze memory integrity against known baselines. In high-volume environments (e.g., >500 endpoints), this synchronized activity generates a burst of events that mimics an anomalous lateral movement or unauthorized execution pattern.
  • Filter/Exclusion: Create a rule exclusion for the specific process path C:\Program Files\CrowdStrike\csagent.exe when executed by the system account (NT AUTHORITY\SYSTEM) during the maintenance window of 01:30–02:30 UTC. Additionally, filter events where the source IP is within the internal management subnet (e.g., 10.50.10.0/24).

• Automated Patch Deployment via Microsoft SCCM (Configuration Manager)

  • Scenario: During a Tuesday morning patch cycle, the SCCM client service initiates a software update deployment. The deployment agent invokes the Spora component to validate package hashes before installation and uses Cerber ek to enforce application whitelisting policies on the newly installed binaries. This results in legitimate “new process creation” alerts that are indistinguishable from potential malware execution without context.
  • Filter/Exclusion: Exclude events where the parent process is ccmexec.exe (SCCM) or UpdateOrchestrator.exe. Furthermore, add a filter to suppress alerts if the file hash matches any entry in the organization’s ”