URLhaus: opendir Malicious URLs

Hunt Hypothesis

This detection identifies adversary behavior where attackers leverage malicious URLs associated with the “opendir” campaign to deliver payloads that exploit directory traversal vulnerabilities or initiate unauthorized file access. A SOC team should proactively hunt for these indicators in Azure Sentinel because early identification of opendir-tagged traffic allows for immediate containment of potential data exfiltration attempts and prevents lateral movement within the network before broader compromise occurs.

IOC Summary

Threat: opendir Total URLs: 6 Active URLs: 4

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: opendir
let malicious_domains = dynamic(["103.229.53.84"]);
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(["103.229.53.84"]);
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 and corresponding filters for the URLhaus: opendir Malicious URLs detection rule in an enterprise environment:

• Scenario: Automated Software Update Scans by Endpoint Protection Agents

  • Context: Enterprise endpoint protection suites (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or SentinelOne) frequently poll the opendir repository to fetch the latest malware definition signatures and threat intelligence feeds. These agents often initiate outbound HTTPS connections to known URLhaus endpoints, which can be misidentified as suspicious browser activity if the agent’s process name isn’t explicitly whitelisted.
  • Suggested Filter: Exclude traffic originating from specific service processes (e.g., C:\Program Files\CrowdStrike\csagent.exe or C:\Windows\System32\MsMpEng.exe) where the destination URL contains known update domains like updates.opendir.com or feed.opendir.net.

• Scenario: Scheduled Inventory and Compliance Reporting Jobs

  • Context: IT Asset Management tools (e.g., ServiceNow Discovery, Ivanti Neurons, or SolarWinds) run nightly scheduled jobs to inventory software installations. These jobs often query external databases via the opendir API to verify license validity and version numbers, triggering the rule when they fetch metadata from the malicious URL list used for validation.
  • Suggested Filter: Create an exclusion based on the source IP range of the dedicated reporting server (e.g., 10.20.50.x) combined with a time-based window (e.g., 02:00–04:00 UTC) where these scheduled inventory jobs are known to execute.

• Scenario: CI/CD Pipeline Artifact Retrieval

  • Context: DevOps teams utilizing Jenkins, GitLab CI, or