URLhaus: js Malicious URLs

Hunt Hypothesis

This detection identifies adversary activity involving JavaScript-based threats by monitoring traffic to known malicious URLs flagged by URLhaus. Proactively hunting for these indicators in Azure Sentinel is critical because JavaScript-driven attacks often serve as initial footholds for lateral movement and data exfiltration that may bypass standard signature-based defenses.

IOC Summary

Threat: js Total URLs: 2 Active URLs: 2

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: js
let malicious_domains = dynamic(["192.236.217.68", "192.236.217.77"]);
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(["192.236.217.68", "192.236.217.77"]);
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: js Malicious URLs detection rule in an enterprise environment, along with suggested filters or exclusions:

• Software Update Mechanisms via JavaScript Checksums

  • Scenario: Enterprise deployment tools like Microsoft System Center Configuration Manager (SCCM) or Jamf Pro frequently execute scheduled jobs to verify the integrity of software packages. These agents often fetch dynamic JavaScript manifest files from vendor update servers (e.g., update.microsoft.com or cdn.jamfcloud.com) which may be flagged by URLhaus as “js” if they contain embedded tracking scripts or recently updated code signatures that haven’t yet been whitelisted in the threat intelligence feed.
  • Suggested Filter: Exclude traffic originating from known management server IP ranges (e.g., 10.20.x.x for SCCM) accessing specific vendor domains where the User-Agent string contains “SCCM” or “JamfProAgent,” provided the HTTP status code is 200 and no subsequent download of executable payloads occurs immediately after.

• Browser-Based Admin Portals with Third-Party Analytics

  • Scenario: Administrators accessing internal dashboards (e.g., ServiceNow, Salesforce, or custom SharePoint portals) often trigger this rule when the browser loads third-party analytics scripts (such as Google Analytics, New Relic, or Dynatrace) embedded within the portal’s JavaScript. URLhaus may flag these external script sources if they share a domain with known malicious JS delivery networks, even though the traffic is purely informational and initiated by human administrative activity during business hours.
  • Suggested Filter: Create an exclusion for URLs containing specific query parameters common to analytics (e.g., ?ga=, ?nrjs=) or domains ending in .google-analytics.com and `.new