ThreatFox: Unknown Stealer IOCs

Hunt Hypothesis

This hunt targets adversary behavior where an unknown stealer malware executes specific indicators of compromise to exfiltrate sensitive credentials and data from endpoints within the Azure environment. Proactively hunting for these three IOCs is critical because early detection allows the SOC team to isolate compromised assets before the stealer can establish persistence or spread laterally across the network.

IOC Summary

Malware Family: Unknown Stealer Total IOCs: 3 IOC Types: url

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - Unknown Stealer
let malicious_urls = dynamic(["https://shadowcape.online/babayla/zor/yarisirlar/", "https://shadowcape.online/mods/api/log-download", "https://shadowcape.online/?p="]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — Unknown Stealer

False Positive Guidance

Here are four specific false positive scenarios for the ThreatFox: Unknown Stealer IOCs rule in an enterprise environment, including suggested filters or exclusions:

• Endpoint Protection Management Console Scans

  • Scenario: The centralized management console (e.g., CrowdStrike Falcon, SentinelOne, or Microsoft Defender for Endpoint) performs a scheduled “Deep Scan” or “Threat Intelligence Update.” During this process, the agent downloads and temporarily caches known threat definition files or IOCs from the vendor’s cloud repository. These cached files may match the hash patterns of the Unknown Stealer family before being fully indexed as trusted by the local OS.
  • Filter/Exclusion: Create a rule exclusion for processes originating from the specific endpoint management service (e.g., C:\Program Files\CrowdStrike\fs.exe or MsMpEng.exe) when accessing files within their designated installation and cache directories (%ProgramData%\CrowdStrike, %LocalAppData%\Microsoft\Windows Defender).

• Software Deployment via Configuration Management

  • Scenario: An automated deployment job using Ansible, SCCM (System Center Configuration Manager), or Intune pushes a new application update to a batch of workstations. The deployment agent extracts installation packages (MSI/EXE) containing embedded libraries or third-party components that share cryptographic signatures with the Unknown Stealer IOCs. This often occurs during off-hours maintenance windows when large file transfers are common.
  • Filter/Exclusion: Exclude alerts where the parent process is a known configuration management agent (e.g., ccmexec.exe, Ansible-Runner, or IntuneManagementExtension) and the file path resides within the temporary deployment staging folder (e.g., C:\Windows\CCMCache or C:\Temp\DeploymentStaging).

• **IT Admin