URLhaus: elf Malicious URLs

Hunt Hypothesis

This rule detects the presence of malicious URLs associated with the ELF malware family, indicating potential compromise or active exploitation attempts within the environment. Proactively hunting for these indicators allows the SOC team to identify early-stage intrusions or lateral movement vectors before the ELF payload can establish persistence or escalate privileges in Azure Sentinel.

IOC Summary

Threat: elf Total URLs: 11 Active URLs: 2

KQL: Url Dns Hunt

// Hunt for DNS resolution of URLhaus malicious domains
// Threat: elf
let malicious_domains = dynamic(["162.249.125.145", "123.161.90.221"]);
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(["162.249.125.145", "123.161.90.221"]);
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 Update Checks: Older line-of-business applications (e.g., specific versions of SAP GUI, Oracle Forms, or legacy Java-based tools) may still reference outdated or decommissioned vendor update endpoints that have been re-registered or flagged by URLhaus due to historical compromise.
  • Filter/Exclusion: Exclude URLs containing specific legacy vendor domains (e.g., *.sap.com, *.oracle.com) if the application is known to be patched and isolated, or whitelist the specific User-Agent string generated by the legacy client.
• Internal Development/Staging Environments: Developers or QA teams may host test builds or mock APIs on internal IIS/Apache servers that inadvertently use public IP addresses or domains previously associated with ELF campaigns (e.g., if a staging server was briefly exposed to the internet or uses a shared cloud IP).
  • Filter/Exclusion: Exclude traffic where the source IP is within the internal RFC1918 range (10.x.x.x, 172.16.x.x, 192.168.x.x) and the destination port is standard HTTP/HTTPS (80/443), or filter out known internal hostnames (e.g., *.corp.local, *.staging.internal).
• Scheduled Backup or Sync Jobs: Automated backup solutions (e.g., Veeam, Commvault) or file sync tools (e.g., rsync, Unison) may connect to remote storage endpoints or peer nodes that share IP addresses or domain names with known ELF infrastructure, particularly if using cloud-based object storage with shared endpoints.
  • Filter/Exclusion: Exclude connections initiated by specific service accounts (e.g., svc-backup, svc-sync) or filter by the specific process name (e.g., VeeamBackup.exe, rsync) if the URL matches a