ThreatFox: VoltStealer IOCs

Hunt Hypothesis

This hunt targets known indicators of compromise associated with VoltStealer, a credential-stealing malware frequently deployed in phishing campaigns to compromise user sessions. Proactively searching for these IOCs in Azure Sentinel allows the SOC to identify potentially infected endpoints or compromised identities before the adversary can escalate privileges or exfiltrate sensitive data.

IOC Summary

Malware Family: VoltStealer Total IOCs: 3 IOC Types: sha1_hash, md5_hash, sha256_hash

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - VoltStealer
let malicious_hashes = dynamic(["c9fd4ec3ea940456b89dc7c7192f67ba9b7f258fdb118f6dbfe195fce981c973", "8be112ec619ef287abb5ad74186ab04882368e40", "50eb3d47e565d0e7fcd861032e806de5"]);
DeviceFileEvents
| where SHA256 in (malicious_hashes) or SHA1 in (malicious_hashes) or MD5 in (malicious_hashes)
| project Timestamp, DeviceName, FileName, FolderPath, SHA256, InitiatingProcessFileName
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — VoltStealer

False Positive Guidance

• Scenario: A DevOps engineer uses ansible or Terraform to deploy a new microservice, where the deployment script downloads a pre-built binary or container image from a public registry (e.g., Docker Hub, JFrog Artifactory) that happens to share a hash or URL pattern with a known VoltStealer IOC.
  • Filter/Exclusion: Exclude alerts where the source IP is within the internal CI/CD network range (e.g., 10.10.50.0/24) AND the user account belongs to the svc-ci-cd service group.
• Scenario: An IT administrator performs a manual patching task using winget or choco to install a specific version of a third-party application (e.g., 7-Zip or Notepad++) from a mirror site that was recently added to the ThreatFox IOC list due to a compromised build, but is still trusted internally.
  • Filter/Exclusion: Exclude alerts if the process name is winget.exe or choco.exe AND the parent process is cmd.exe or powershell.exe initiated by an administrator group (Domain Admins or IT Admins).
• Scenario: A security team runs a YARA rule or memory scan using Volatility3 or APEX to hunt for VoltStealer remnants in a live system, causing the tool itself to download or reference the IOC hashes/URLs during the analysis phase.
  • Filter/Exclusion: Exclude alerts where the initiating process is a known forensic tool (e.g., volatility3.exe, apex.exe, yara.exe) AND the user account is in the SOC Forensics security group.
• Scenario: A legacy application server runs a scheduled task via `Task