ThreatFox: Vjw0rm IOCs

Hunt Hypothesis

This hunt hypothesis targets adversary behavior where malicious actors leverage specific ThreatFox indicators of compromise to establish persistence and execute command-and-control communications within the Azure environment. The SOC team should proactively hunt for these Vjw0rm IOCs in Azure Sentinel to identify early-stage infections before they escalate into broader lateral movement or data exfiltration incidents.

IOC Summary

Malware Family: Vjw0rm Total IOCs: 14 IOC Types: domain

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Vjw0rm
let malicious_domains = dynamic(["fiscalnotificacionmunicipal.store", "fundacionolipica.store", "notificadorlocalsolionesfis.store", "www.remicionesexternas.store", "www.firmaprincipal.store", "comidarapidas.store", "solicitudelarchivo.store", "calzadoswer.store", "cominiucadosinternos.store", "notificacionesnacionales.store", "cpantalonesnegro.store", "etiendasb.store", "bpadellcali.store", "detalleselparaiso.store"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — Vjw0rm

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: Vjw0rm IOCs detection rule in an enterprise environment, along with recommended filters or exclusions:

• Enterprise Antivirus Definition Updates

  • Scenario: The organization’s endpoint protection suite (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or Symantec) performs a scheduled daily update of its virus definition database. During this process, the AV engine downloads and unpacks large signature files that may contain hash values matching the Vjw0rm IOCs, triggering alerts on multiple endpoints simultaneously.
  • Filter/Exclusion: Create an exclusion rule to suppress alerts originating from known AV service accounts (e.g., svc-av-updater) or specific process paths related to the AV engine’s update module (e.g., C:\Program Files\Microsoft Defender\MpCmdRun.exe with arguments containing /update).

• Software Deployment via Configuration Management

  • Scenario: The IT operations team utilizes a configuration management tool like Ansible, Chef, or SCCM (System Center Configuration Manager) to deploy a new patch or application package. The deployment script extracts an archive containing the Vjw0rm IOC artifacts as part of the installation payload, causing file creation events that match the threat signature on the target servers.
  • Filter/Exclusion: Exclude alerts where the parent process is identified as the configuration management agent (e.g., Ansible Runner, ccmexec.exe, or chef-client) and the event source IP belongs to the internal patching server subnet.

• Scheduled Backup and Archive Operations

  • Scenario: A nightly backup job executed by tools such as Veeam Backup & Replication, Commvault, or Rubrik archives critical data directories. If the Vjw0rm IOCs are embedded