ThreatFox: Vidar IOCs

Hunt Hypothesis

The hunt hypothesis detects potential Vidar malware activity through suspicious network connections and file artifacts associated with data exfiltration. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate advanced persistent threats that leverage compromised credentials to steal sensitive information.

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(["fre.duitsm188.top", "fre.canamrental.com"]);
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://fre.canamrental.com/", "https://fre.duitsm188.top/"]);
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

• Scenario: Legitimate Scheduled Job for System Maintenance
  Description: A scheduled task runs a legitimate maintenance script that uses certutil to verify SSL certificates, which may trigger the rule due to the presence of certutil in the command line.
  Filter/Exclusion: Exclude processes initiated by schtasks.exe or tasks with a known maintenance script name (e.g., SystemMaintenance.bat).

• Scenario: Admin Task Using PowerShell to Retrieve System Information
  Description: An administrator uses PowerShell to gather system information using certutil or Get-ChildItem to check for certificate stores, which may be flagged due to similarity with malicious activity.
  Filter/Exclusion: Exclude processes initiated by powershell.exe with a known admin script or command line containing Get-ChildItem or certutil in a non-malicious context.

• Scenario: Legitimate Use of certutil for Certificate Management
  Description: A system administrator uses certutil to manage or renew SSL/TLS certificates, which may be flagged due to its association with malicious activity.
  Filter/Exclusion: Exclude processes where certutil is used in conjunction with certificate management tools like certmgr.msc or with known certificate file paths.

• Scenario: Automated Backup Process Using certutil for Encryption
  Description: A backup process uses certutil to encrypt backup files, which may be flagged due to the presence of certutil in the command line.
  Filter/Exclusion: Exclude processes initiated by a known backup service (e.g., VeeamBackup.exe, AcronisBackup.exe) or those using certutil for encryption in a known backup directory.

• Scenario: Use of certutil in a Security Tool for Threat Detection
  *Description