ThreatFox: Vidar IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the execution of Vidar malware components by monitoring network and endpoint telemetry against four specific threat intelligence indicators. Proactively hunting these IOCs in Azure Sentinel is critical to rapidly identify early-stage infections and mitigate data exfiltration risks before they escalate into broader organizational compromises.

IOC Summary

Malware Family: Vidar Total IOCs: 4 IOC Types: domain, url

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Vidar
let malicious_domains = dynamic(["hat.jurangsm188.top", "hat.realmadridiran.news"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - Vidar
let malicious_urls = dynamic(["https://hat.jurangsm188.top/", "https://hat.realmadridiran.news/"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Vidar

False Positive Guidance

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

• Endpoint Protection Scanning of Quarantine Archives

  • Scenario: Enterprise Endpoint Detection and Response (EDR) agents (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) performing scheduled deep scans on the C:\ProgramData\ThreatFox\Quarantine directory. The Vidar IOCs often include hash-based indicators that match benign files previously downloaded by security teams or archived threat intelligence feeds stored in this specific path.
  • Filter/Exclusion: Exclude processes belonging to known EDR service accounts (e.g., NT SERVICE\CrowdStrikeService, SYSTEM) when the file path contains \Quarantine\ or \ThreatIntel\. Additionally, filter out events where the process command line includes specific scan flags like /deep-scan or -archive-check.

• Internal Threat Intelligence Feed Synchronization

  • Scenario: The organization’s Security Information and Event Management (SIEM) or dedicated threat intelligence platform (e.g., Splunk Phantom, Palo Alto Cortex XSOAR) running a scheduled job to ingest the latest Vidar IOC feed from the internal repository. This process downloads and validates the JSON/TXT files containing the 4 specific IOCs, triggering file creation and hash verification events that mimic an active infection scan.
  • Filter/Exclusion: Create an exclusion rule for network traffic and file system events originating from the management subnet (e.g., 10.20.50.x) during scheduled maintenance windows (e.g., 02:00–04:00 UTC). Specifically, exclude processes named feed_sync_service.exe or Python scripts (python3 feed_ingestion.py) running under the svc_threat_intel