ThreatFox: Vidar IOCs

Hunt Hypothesis

This hunt hypothesis targets adversary behavior where the Vidar credential-stealing malware infiltrates systems to exfiltrate banking credentials and sensitive data through encrypted channels. A proactive search in Azure Sentinel is essential to identify early indicators of this high-severity threat, enabling rapid containment before critical financial information is compromised.

IOC Summary

Malware Family: Vidar Total IOCs: 5 IOC Types: domain, url

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Vidar
let malicious_domains = dynamic(["mua.y8slot.net"]);
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://impact24-7.com.au/", "https://mua.y8slot.net/", "https://bioformula.cl/", "https://62.238.60.47"]);
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 targeted filters and exclusions tailored for an enterprise environment:

• Scenario: Legitimate Cloud Backup Agent Communication

  • Context: Enterprise backup solutions (e.g., Veeam, Commvault) often utilize encrypted channels to exfiltrate large volumes of system data and credential snapshots to cloud repositories. Vidar’s detection logic may flag the high-volume encrypted outbound traffic from these agents as suspicious exfiltration behavior similar to Vidar’s signature.
  • Filter/Exclusion: Create an exclusion rule for processes with known hashes or specific service names (e.g., VeeamBackupService.exe, commvault.cmd) communicating on standard backup ports (e.g., 443, 8080) to approved cloud IP ranges.

• Scenario: Scheduled Credential Rotation via PowerShell

  • Context: IT operations teams frequently run scheduled PowerShell jobs (Task Scheduler) that query Active Directory or internal vaults (like CyberArk or HashiCorp Vault) to rotate service account credentials. These scripts often establish encrypted connections and transmit credential data, mimicking Vidar’s credential-stealing behavior.
  • Filter/Exclusion: Exclude traffic originating from the powershell.exe process when launched by a specific trusted user (e.g., DOMAIN\BackupAdmin) or running under a known scheduled task ID (e.g., “Daily_Cred_Rotation_Task”).

• Scenario: Endpoint DLP Agent Scanning and Reporting

  • Context: Data Loss Prevention (DLP) agents installed on endpoints (such as Symantec DLP, Forcepoint, or Microsoft Purview) constantly scan files for sensitive data patterns and transmit reports to the central management console. This scanning and reporting mechanism involves encrypted exfiltration of system information and potential banking