ThreatFox: Vidar IOCs

Hunt Hypothesis

This hypothesis posits that adversaries are actively deploying the Vidar infostealer to exfiltrate sensitive credentials and financial data through known indicators of compromise within the Azure environment. The SOC team should proactively hunt for these specific IOCs in Azure Sentinel to rapidly identify early-stage infections and mitigate potential lateral movement before critical assets are compromised.

IOC Summary

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

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Vidar
let malicious_domains = dynamic(["gog.tb88tank.top"]);
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://ironcladsportfishing.com/", "https://ewbn.org/", "https://alumnofprojects.co.il/"]);
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 Policy Updates via CrowdStrike Falcon or Microsoft Defender

  • Scenario: Security administrators push a global policy update that includes new definitions or heuristic signatures specifically targeting the Vidar malware family. The deployment process downloads and executes the associated IOCs (hashes, file paths) on all managed endpoints to verify compatibility before full rollout.
  • Filter/Exclusion: Create an exclusion for processes spawned by known EDR daemons (e.g., C:\Program Files\CrowdStrike\fs.exe or MsMpEng.exe) when accessing Vidar-related file paths, provided the user context is a Domain Admin or Service Account.

• Scheduled Vulnerability Scanning with Tenable Nessus or Qualys

  • Scenario: A scheduled weekly vulnerability scan executes on critical servers to check for known malware indicators. The scanner’s agent downloads and analyzes Vidar-specific IOC files (such as sample executables or configuration scripts) stored in a shared network repository (\\FileServer\SecRepo\VidarSamples) to validate the detection baseline.
  • Filter/Exclusion: Exclude traffic and file access events originating from the vulnerability scanning service accounts (e.g., svc-tenable-scanner or QualysAgentService) accessing the specific network share path where Vidar test artifacts are stored.

• Automated Threat Intelligence Feed Integration via Splunk or Sentinel

  • Scenario: The SIEM platform runs a scheduled hourly job to ingest threat intelligence feeds from external sources (including ThreatFox). This process involves downloading and parsing JSON/XML files containing the latest Vidar IOCs, which triggers file creation and network connections matching the rule’s detection logic.
  • Filter/Exclusion: