URLhaus: 9d2ca3 Malicious URLs

Hunt Hypothesis

This hunt targets adversary behavior characterized by user or system access to specific malicious web resources identified by the URLhaus intelligence feed under signature 9d2ca3. Proactively hunting for these indicators in Azure Sentinel is critical because early detection of these high-severity URLs can prevent initial compromise vectors and limit lateral movement before broader infection occurs.

IOC Summary

Threat: 9d2ca3 Total URLs: 2 Active URLs: 1

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: 9d2ca3
let malicious_domains = dynamic(["91.92.242.236"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses
| order by TimeGenerated desc

KQL: Url Proxy Hunt

// Hunt for web traffic to URLhaus malicious domains
let malicious_domains = dynamic(["91.92.242.236"]);
CommonSecurityLog
| where RequestURL has_any (malicious_domains) or DestinationHostName has_any (malicious_domains)
| project TimeGenerated, SourceIP, RequestURL, DestinationHostName, DeviceAction
| order by TimeGenerated desc

Required Data Sources

References

• URLhaus

False Positive Guidance

Here are specific false positive scenarios for the URLhaus: 9d2ca3 Malicious URLs detection rule in an enterprise environment, along with suggested filters and exclusions:

• Automated Software Update Scans by Antivirus Agents

  • Scenario: Enterprise endpoint protection suites (e.g., CrowdStrike Falcon, SentinelOne, or Symantec Endpoint Protection) frequently perform background checks against known threat intelligence feeds. During these scheduled scans, the agents may generate HTTP/HTTPS requests to URLhaus APIs or specific mirror sites tagged with 9d2ca3 to verify signature databases, even when no actual user activity is occurring.
  • Filter/Exclusion: Create an exclusion rule based on the Process Name (e.g., C:\Program Files\CrowdStrike\fsa.exe) and restrict the alert scope to traffic originating from the Service Account used by the AV management console, rather than interactive user sessions.

• IT Admin Manual Verification via Browser Extensions

  • Scenario: Security administrators or help desk staff often manually investigate suspicious links using browser extensions like WOT (Web of Trust), McAfee WebAdvisor, or Bitdefender TrafficLight. When an admin clicks a link to verify its reputation, the extension’s background service may trigger a secondary lookup request directly to the URLhaus infrastructure tagged as 9d2ca3, mimicking a user-initiated malicious visit.
  • Filter/Exclusion: Exclude traffic where the User Agent string contains keywords specific to security extensions (e.g., “WOT-Extension”, “McAfee-WebAdvisor”) and limit the scope to the OU (Organizational Unit) containing Security Operations staff or IT Administrators.

• Scheduled Compliance Reporting Jobs

  • Scenario: Automated compliance tools such as Qualys, **