URLhaus: arm Malicious URLs

Hunt Hypothesis

This detection identifies adversary activity involving access to ARM-tagged malicious URLs identified by the URLhaus threat intelligence feed, which often indicate early-stage command and control or phishing campaigns targeting Azure workloads. Proactively hunting for these specific indicators in Azure Sentinel allows the SOC team to rapidly isolate compromised endpoints and block associated network traffic before adversaries can establish persistence or exfiltrate sensitive data.

IOC Summary

Threat: arm Total URLs: 4 Active URLs: 0

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: arm
let malicious_domains = dynamic(["31.56.209.70"]);
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(["31.56.209.70"]);
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 5 specific false positive scenarios for the URLhaus: arm Malicious URLs detection rule, including tailored filters and exclusions suitable for an enterprise environment:

• Scenario: Automated Security Tool Updates via Cloud Repositories

  • Context: Endpoint Detection and Response (EDR) agents like CrowdStrike Falcon or Microsoft Defender for Endpoint frequently query the arm (Android Runtime/Architecture) specific update servers to fetch definition updates. These URLs often carry a generic “arm” tag in threat intelligence feeds but are part of standard maintenance cycles.
  • Filter/Exclusion: Create an exclusion rule that ignores alerts where the source process is C:\Program Files\CrowdStrike\fsqa.exe (or equivalent EDR updater) and the destination domain matches known update endpoints such as *.falcon.crowdstrike.com or *.update.microsoft.com.

• Scenario: Scheduled Mobile Device Management (MDM) Policy Syncs

  • Context: Enterprise MDM solutions like Microsoft Intune or Jamf Pro push configuration profiles to Android devices. During these sync windows, the system generates requests to ARM-specific API endpoints to verify device compliance and download policy manifests, which can be flagged as “arm” malicious traffic by URLhaus due to high volume or new certificate chains.
  • Filter/Exclusion: Exclude traffic originating from the service account MDM-Service-Account during scheduled maintenance windows (e.g., 02:00–04:00 UTC). Additionally, whitelist specific Intune endpoints like manage.microsoft.com and intunemanagement.azurewebsites.net.

• Scenario: CI/CD Pipeline Artifact Retrieval for ARM64 Builds

  • Context: DevOps teams using Azure DevOps or Jenkins often trigger nightly builds for