ThreatFox: ValleyRAT IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the execution of known ValleyRAT remote access trojan indicators to establish persistent command and control channels within the environment. Proactively hunting these specific IOCs in Azure Sentinel is critical because early detection of this high-severity threat enables rapid containment before attackers can exfiltrate sensitive data or pivot laterally across the network.

IOC Summary

Malware Family: ValleyRAT Total IOCs: 3 IOC Types: ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - ValleyRAT
let malicious_ips = dynamic(["192.253.228.193", "154.82.93.200"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["192.253.228.193", "154.82.93.200"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — ValleyRAT

False Positive Guidance

Here are 5 specific false positive scenarios for the ThreatFox: ValleyRAT IOCs detection rule in an enterprise environment, along with suggested filters or exclusions:

• Endpoint Protection Scanning of Quarantine Archives

  • Scenario: The organization’s EDR (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) performs a scheduled deep scan of the C:\ProgramData\Quarantine directory. This directory contains archived, benign versions of legacy software that happen to share file hashes with known ValleyRAT IOCs due to shared code libraries or previous updates from the same vendor.
  • Filter/Exclusion: Exclude paths matching *\Quarantine*, *\Backup*, and *\Archive* from the detection logic, provided the process initiating the scan is a trusted security agent (e.g., csagent.exe or MsMpEng.exe).

• IT Administration: Software Deployment via SCCM/Intune

  • Scenario: The IT Operations team executes a mass deployment of a third-party utility tool using Microsoft Endpoint Configuration Manager (SCCM) or Intune. During the installation phase, the installer extracts temporary files to %TEMP% that match ValleyRAT IOCs before the final application is fully installed and signed by the internal PKI.
  • Filter/Exclusion: Create an exclusion for processes running under the context of ccmexec.exe (SCCM) or Microsoft.IntuneManagementExtension.exe, specifically targeting file paths within %TEMP% and %PROGRAMDATA%\Microsoft\Intune.

• Scheduled Maintenance: Antivirus Signature Updates

  • Scenario: A nightly scheduled task triggers the antivirus engine to download and validate new signature definitions. The update package includes a sandboxed analysis of recent threat intelligence feeds, which temporarily generates file artifacts matching ValleyRAT IOCs as part of