ThreatFox: Vidar IOCs

Hunt Hypothesis

This hunt detects the presence of Vidar malware, a credential-stealing trojan that actively harvests sensitive authentication data and exfiltrates it from compromised endpoints. Proactively hunting for these indicators in Azure Sentinel is critical to identify early-stage infections before adversaries can leverage stolen credentials to establish persistent access or pivot deeper into the network.

IOC Summary

Malware Family: Vidar Total IOCs: 7 IOC Types: domain, url

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Vidar
let malicious_domains = dynamic(["ran.bayototo.org", "web.bayototo.org", "ign.bayototo.org"]);
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://ran.bayototo.org/", "https://web.bayototo.org/", "https://www.bayototo.org/", "https://ign.bayototo.org/"]);
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 5 specific false positive scenarios for the ThreatFox: Vidar IOCs detection rule, including context and suggested filters/exclusions tailored for an enterprise environment:

• Endpoint Protection Console Updates

  • Scenario: The central management server (e.g., Microsoft Defender for Endpoint or CrowdStrike Falcon) pushes a definition update or policy change that includes a new IOC hash matching the Vidar signature. This often triggers when the update service (UpdateService) downloads and installs the latest threat intelligence feed, which may contain overlapping hashes with known benign enterprise software components.
  • Filter/Exclusion: Exclude processes originating from the specific Endpoint Protection management server hostname (e.g., EP-MS01) or filter out alerts where the parent process is DefenderService.exe / FalconSensor.exe.

• Scheduled Credential Backup Jobs

  • Scenario: Automated backup solutions like Veeam, Commvault, or Acronis run scheduled jobs to back up Active Directory user credentials and password databases. Since Vidar is a credential-stealing trojan, the heavy I/O activity of these tools reading NTDS.dit or accessing LSA secrets can mimic the behavior of Vidar exfiltrating data, triggering the rule during nightly maintenance windows (e.g., 02:00 – 04:00).
  • Filter/Exclusion: Create a time-based exclusion for alerts generated between 01:00 and 05:00 UTC on weekdays where the source process is VeeamTransportService.exe or CommServe.exe.

• Identity Management & SSO Provisioning

  • Scenario: Identity Governance tools such as SailPoint, Okta Workforce, or Microsoft Entra ID (Azure AD) perform routine synchronization tasks to map user attributes and refresh tokens. These services frequently access credential stores and