URLhaus: d52f85 Malicious URLs

Hunt Hypothesis

This hunt targets adversary behavior where compromised hosts initiate connections to known malicious URLs associated with the d52f85 threat signature, indicating potential command-and-control communication or phishing payload delivery. Proactively hunting for these specific indicators in Azure Sentinel is critical to rapidly identify and isolate affected assets before they can exfiltrate sensitive data or propagate lateral movement across the enterprise network.

IOC Summary

Threat: d52f85 Total URLs: 3 Active URLs: 2

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: d52f85
let malicious_domains = dynamic(["cdn.cs-elect.ru", "ezcheats-market.com"]);
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(["cdn.cs-elect.ru", "ezcheats-market.com"]);
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 4 specific false positive scenarios for the URLhaus: d52f85 Malicious URLs detection rule, tailored for an enterprise environment:

• Automated Software Update Scans via Patch Management Tools

  • Scenario: Enterprise patch management solutions like Microsoft Endpoint Configuration Manager (MECM/SCCM) or Ivanti Neurons frequently scan internal update repositories. These tools may query external vendor endpoints to verify the integrity of upcoming patches, triggering connections to URLs that URLhaus has flagged as d52f85 due to historical reputation issues, even though the current traffic is benign and part of a standard maintenance window.
  • Filter/Exclusion: Create an exclusion for source IP ranges belonging to the Patch Management servers (e.g., 10.x.x.x/24) or filter out destination URLs containing known vendor domains (e.g., *.update.microsoft.com, *.download.adobe.com) during scheduled maintenance windows (e.g., 02:00–06:00 UTC).

• Third-Party Compliance and Security Scanner Probes

  • Scenario: External security assessment tools such as Qualys Cloud Agent, Tenable Nessus, or Rapid7 InsightVM perform continuous vulnerability assessments. These agents often probe external reference URLs to validate certificate chains or check for known vulnerabilities, generating traffic that matches the d52f85 signature. The detection logic may flag these probes as malicious because they originate from shared service IPs rather than user workstations.
  • Filter/Exclusion: Exclude traffic originating from the specific IP addresses of the security scanning appliances or filter by process name (e.g., qualysagent.exe, tenable-agent) to distinguish automated scanner activity from interactive user browsing sessions.

• Scheduled Data Backup and Synchronization Jobs *