ThreatFox: Vidar IOCs

Hunt Hypothesis

This detection identifies adversary activity involving the Vidar infostealer by monitoring for four specific indicators of compromise known to target sensitive credentials and financial data. Proactively hunting for these signals in Azure Sentinel is critical because early identification of Vidar’s presence allows the SOC team to contain potential data exfiltration before attackers establish persistence or escalate their attack chain.

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(["nhg.sm188dadu.top", "nhg.1131gg.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://nhg.sm188dadu.top/", "https://nhg.1131gg.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 3-5 specific false positive scenarios for the ThreatFox: Vidar IOCs detection rule, including suggested filters and exclusions tailored for a legitimate enterprise environment:

• Endpoint Protection Scanning of Known Artifacts

  • Scenario: Enterprise Endpoint Detection and Response (EDR) solutions like CrowdStrike Falcon, Microsoft Defender for Endpoint, or SentinelOne frequently scan the system registry, file system, and memory. If these tools have recently updated their definition packs to include Vidar signatures, they may generate network connections or process executions matching the rule’s IOCs (e.g., specific DLL loads or registry key checks) as part of a routine health check rather than an active infection.
  • Filter/Exclusion: Exclude processes belonging to known security vendors. Add a filter to ignore alerts where ProcessName matches *FalconSensor.exe, *MsMpEng.exe, or *SentinelOneAgent.exe.

• Scheduled Maintenance and Patch Deployment Jobs

  • Scenario: IT Operations teams often utilize tools like Microsoft SCCM (Configuration Manager), Ivanti Neurons, or Ansible Tower to deploy patches or run nightly maintenance scripts. If a scheduled job involves updating the “Vidar” module within an internal security suite or running a legacy script that references Vidar-specific registry keys, it will trigger the detection logic as a new IOC match.
  • Filter/Exclusion: Create a time-based exclusion for alerts occurring during defined maintenance windows (e.g., 02:00 – 04:00 UTC). Additionally, exclude alerts where ParentProcessName is *ccmexec.exe or *ansible-runner, indicating the activity was initiated by a deployment engine.

• Internal Security Automation and Threat Hunting Scripts

  • Scenario: The internal SOC