ThreatFox: Kimwolf IOCs

Hunt Hypothesis

This detection rule identifies adversary activity linked to the Kimwolf malware by monitoring specific indicators of compromise (IOCs) known to facilitate its initial infection and lateral movement. A proactive hunt is essential in Azure Sentinel to rapidly uncover early-stage compromises before they escalate into broader data exfiltration or ransomware deployment, ensuring timely containment of this high-severity threat.

IOC Summary

Malware Family: Kimwolf Total IOCs: 3 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Kimwolf
let malicious_ips = dynamic(["172.235.182.165", "172.235.191.232", "172.233.33.8"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["172.235.182.165", "172.235.191.232", "172.233.33.8"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Kimwolf

False Positive Guidance

Here are the documented false positive scenarios for the ThreatFox: Kimwolf IOCs detection rule, including specific triggers and recommended filters:

• Scenario 1: Scheduled Antivirus Definition Updates

  • Trigger: The enterprise endpoint protection suite (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec Endpoint Protection) initiates a nightly update cycle. During this process, the security agent downloads and validates new signature databases from the vendor’s cloud repository, which may contain hash values matching Kimwolf IOCs used by the vendor’s own telemetry services.
  • Filter/Exclusion: Create an exclusion rule based on the specific Process Name of the AV service (e.g., C:\Program Files\CrowdStrike\fsqa.exe or MsMpEng.exe) and restrict the detection to exclude traffic originating from known corporate update servers (e.g., WSUS or SCCM distribution points) during maintenance windows (02:00 – 04:00 local time).

• Scenario 2: Legacy Internal Reporting Dashboard Access

  • Trigger: A scheduled internal business intelligence job runs on a dedicated reporting server. This job utilizes an older web framework or third-party plugin that embeds a specific JavaScript library or API client known to share a common hash with the Kimwolf IOC set. The job accesses external data feeds via HTTPS, triggering the rule when the browser engine (e.g., Google Chrome running as chrome.exe in kiosk mode) resolves these dependencies.
  • Filter/Exclusion: Implement an exclusion for the specific Host Name or IP Address of the reporting server and filter out events where the User Agent string contains “Internal-Report-Job” or matches a known internal service account (e.g., svc-reporting).

• **Scenario 3: Admin