URLhaus: 31-56-209-210 Malicious URLs

Hunt Hypothesis

This hunt targets potential web-based initial access or command-and-control channels by identifying traffic to a specific cluster of 14 malicious URLs associated with the IP 31.56.209.210. Proactively hunting for these indicators in Azure Sentinel allows the SOC team to detect compromised endpoints or lateral movement attempts before the adversary establishes a persistent foothold or executes further post-compromise actions.

IOC Summary

Threat: 31-56-209-210 Total URLs: 14 Active URLs: 11

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: 31-56-209-210
let malicious_domains = dynamic(["31.56.209.210"]);
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(["31.56.209.210"]);
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

• Legacy Application Health Checks: A legacy internal web application (e.g., an old ASP.NET inventory system) configured with a hardcoded health check endpoint that points to a known IP address for load balancing or failover testing.
  • Filter/Exclusion: Exclude the specific legacy application service account or the source IP range of the application servers from the URLhaus alert if the destination URL matches the known health check path.
• Scheduled Backup Verification Jobs: A nightly scheduled task (e.g., using curl or wget in a Linux cron job or Windows Task Scheduler) that pings a specific external endpoint to verify network connectivity before initiating large data transfers to a cloud storage bucket.
  • Filter/Exclusion: Create a rule to exclude alerts where the source process is cron, systemd, or Task Scheduler and the destination URL matches the specific backup verification endpoint.
• Third-Party API Webhook Testing: Developers or DevOps engineers manually testing webhook integrations for a new microservice by sending test payloads to a staging environment that is temporarily hosted on a public IP address (31-56-209-210) before moving to a private VPC.
  • Filter/Exclusion: Exclude alerts originating from developer workstations or CI/CD pipeline runners (e.g., Jenkins, GitLab Runner) where the user agent or source process indicates a testing tool like Postman, curl, or python-requests.
• DNS Caching or Proxy Refresh: A corporate proxy or DNS cache service (e.g., Squid, Nginx) performing a background refresh or validation of cached resources for a specific domain that resolves to the IP 31-56-209-210 due to a temporary CDN or hosting provider change.
  • Filter/Exclusion: Exclude alerts where the source