ThreatFox: HijackLoader IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the execution of HijackLoader components to establish persistence and exfiltrate credentials within the Azure environment. Proactively hunting for these specific IOCs in Azure Sentinel is critical because early detection of this loader can prevent lateral movement and data theft before the full malware payload is deployed.

IOC Summary

Malware Family: HijackLoader Total IOCs: 2 IOC Types: domain

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - HijackLoader
let malicious_domains = dynamic(["quetrex.com", "mygameszones.com"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — HijackLoader

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: HijackLoader IOCs detection rule in an enterprise environment, along with suggested filters or exclusions:

• Endpoint Protection Policy Updates via Microsoft Intune/SCCM

  • Scenario: During scheduled maintenance windows, the Endpoint Detection and Response (EDR) agent or Antivirus client pushes a definition update that includes a new signature file. This file may contain a hash or URL matching a HijackLoader IOC (e.g., a specific DLL name like loader.dll or a known distribution domain).
  • Filter/Exclusion: Create an exclusion for processes spawned by the EDR service account (e.g., NT SERVICE\Antimalware Service Executable) and specifically exclude file paths located in the vendor’s installation directory (e.g., C:\Program Files\Microsoft Defender Antivirus\ or C:\ProgramData\McAfee\).

• Automated Browser Extension Deployment via Group Policy

  • Scenario: The IT security team deploys a mandatory browser extension (such as a corporate proxy helper or a digital rights management plugin) to all user workstations using Group Policy Objects (GPO). The installation script downloads the extension manifest from an internal repository, which shares a domain name or file hash with a HijackLoader IOC.
  • Filter/Exclusion: Exclude network traffic and file creation events originating from the System account running under the Group Policy Client Service context. Additionally, whitelist specific URLs used by the organization’s Software Distribution Server (e.g., *.internal.company.com) if they match the IOC domain list.

• Third-Party SaaS Integration Health Checks

  • Scenario: A legacy enterprise application (such as a custom HR portal or an ERP module) performs hourly health checks using a background service that calls an external API endpoint to verify connectivity