ThreatFox: Vidar IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the Vidar infostealer by monitoring network and endpoint logs for matches against a curated set of 13 known indicators of compromise. Proactively hunting for these IOCs in Azure Sentinel is critical to identify early-stage infections that could lead to credential theft and lateral movement before they escalate into broader data breaches.

IOC Summary

Malware Family: Vidar Total IOCs: 13 IOC Types: md5_hash, sha1_hash, sha256_hash

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - Vidar
let malicious_hashes = dynamic(["a8b6f506c3465cc8f015edfff552e7f8", "7c221128c38739c84f60a24c495aa2600ea152755be10de0637f2f38c948e087", "42b7294711767ee10032a4513365dc5133c3135f", "5dd22e75f4a2814af58c317fa2e2cd92", "e4260dfd76bd97463a7c875b0764068c7ca26bee", "0344ea912263f13b49d9ad862a88cf4d", "137760599d5ef9de1f6997006a148d0222e4ee442e900e31837fab6d26d0eb76", "23234d20c832f1ce025a3d311f59bb9b33618d20", "91c3431e51158aa800a452222a2404d7b82631ea", "16addb6524e5cf76f4114b0979f715ff", "39298be200be86c3dd12bed11d76959423a33a2d74cb719e0abf76d4e9551b9c", "60f6b6954afed7de062f392a27ec910d", "2d43d592630ad1e012da63ef7279f95dd4a8e94964e12ca2f996051875574fa6"]);
DeviceFileEvents
| where SHA256 in (malicious_hashes) or SHA1 in (malicious_hashes) or MD5 in (malicious_hashes)
| project Timestamp, DeviceName, FileName, FolderPath, SHA256, InitiatingProcessFileName
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Vidar

False Positive Guidance

Here are the false positive scenarios and corresponding exclusions for the ThreatFox: Vidar IOCs detection rule:

• Scenario: Legitimate Software Updates via Patch Management Tools

  • Context: Enterprise patch management solutions like Microsoft Endpoint Configuration Manager (SCCM) or Ivanti Neurons often download and execute installer packages from trusted vendors that share the same hash signatures or domain patterns as Vidar IOCs. These tools frequently trigger the rule when distributing updates for common utilities (e.g., Adobe Reader, Chrome) that utilize similar cryptographic signatures in their installation manifests.
  • Suggested Filter: Exclude processes where ProcessName matches known patch agents (ccmsetup.exe, IvantiAgentService) and the parent process is a scheduled task under the “System” account running during business hours (08:00–18:00).

• Scenario: Scheduled Antivirus or EDR Definition Updates

  • Context: Endpoint Detection and Response (EDR) platforms such as CrowdStrike Falcon, SentinelOne, or Carbon Black perform nightly definition updates. The update service often loads specific DLLs or connects to reputation servers that match the Vidar IOCs’ network patterns or file hashes, causing the hunt package to flag these routine maintenance activities as potential threats.
  • Suggested Filter: Create an exclusion for events where ParentProcessName is the EDR agent (e.g., CnsService.exe, SentinelOneAgent) and the event source is a scheduled job named “Definition Update” running on the local system account.

• Scenario: Admin-Driven Deployment of Internal Line-of-Business Applications

  • Context: IT administrators frequently deploy internal applications using tools like Ansible, Chef, or PowerShell DSC. When these agents push application installers that