ThreatFox: stealler IOCs

Hunt Hypothesis

This detection rule identifies adversary activity linked to the Stealer malware by monitoring specific Indicators of Compromise (IOCs) known to facilitate credential theft and data exfiltration. A proactive hunt is essential in Azure Sentinel to rapidly isolate compromised endpoints before attackers can leverage stolen credentials for lateral movement or persistent access within the environment.

IOC Summary

Malware Family: stealler Total IOCs: 9 IOC Types: sha256_hash, md5_hash, sha1_hash

Type	Value	Threat Type	First Seen	Confidence
sha256_hash	`6167be94c33b2a86f9820cbc1b901700cf5d690193213cb14f44687dd4ed4e18`	payload	2026-08-02	95%
sha1_hash	`4eb4232bee4b5502a1ded712ef3d45b5e553d240`	payload	2026-08-02	95%
md5_hash	`7fdad15d38c44af4039bd440ec83b6e0`	payload	2026-08-02	95%
sha1_hash	`570f06e2cfffccb933f1e4077463b5f24aece6b1`	payload	2026-08-02	95%
md5_hash	`c51ea79875ad62068673cdd298766d23`	payload	2026-08-02	95%
sha256_hash	`bc9eb5dab0d00a0de7c8df3b1d342b5ff435bc8a8cb40a04aaadb869755fe081`	payload	2026-08-02	95%
md5_hash	`3b37fec109ca8e946266eb1bdf8ac1cd`	payload	2026-08-02	95%
sha256_hash	`0f0fd4870160fab8ca35512ecef8425e8c0e733f7a771109598e8efa36fc42e3`	payload	2026-08-02	95%
sha1_hash	`0c1e615682656ef0567acd7a9dc4a1336cd67831`	payload	2026-08-02	95%

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - stealler
let malicious_hashes = dynamic(["6167be94c33b2a86f9820cbc1b901700cf5d690193213cb14f44687dd4ed4e18", "4eb4232bee4b5502a1ded712ef3d45b5e553d240", "7fdad15d38c44af4039bd440ec83b6e0", "570f06e2cfffccb933f1e4077463b5f24aece6b1", "c51ea79875ad62068673cdd298766d23", "bc9eb5dab0d00a0de7c8df3b1d342b5ff435bc8a8cb40a04aaadb869755fe081", "3b37fec109ca8e946266eb1bdf8ac1cd", "0f0fd4870160fab8ca35512ecef8425e8c0e733f7a771109598e8efa36fc42e3", "0c1e615682656ef0567acd7a9dc4a1336cd67831"]);
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

Sentinel Table	Notes
`DeviceFileEvents`	Ensure this data connector is enabled

References

ThreatFox — stealler

False Positive Guidance

Here are specific false positive scenarios and corresponding exclusion strategies for the ThreatFox: stealler IOCs detection rule in an enterprise environment:

Scenario: Endpoint Security Scanning of Quarantined Archives
- Context: Enterprise EDR solutions (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) frequently scan large archive files (.zip, .7z) containing software installers or backup logs. If a legitimate installer package contains a hash that matches one of the Stealer IOCs due to shared code libraries or common dependencies, the rule triggers an alert during routine scans.
- Filter/Exclusion: Create a process-based exclusion for the EDR engine’s scanning service (e.g., C:\Program Files\CrowdStrike\fs_qr.exe or MsMpEng.exe). Configure the detection logic to ignore alerts where the parent process is the EDR scanner and the file extension is .zip, .7z, or .cab.
Scenario: Automated Software Deployment via Configuration Management
- Context: IT Operations teams use tools like Microsoft SCCM (Configuration Manager) or Ansible Tower to push updates. During a scheduled maintenance window, these tools extract and execute deployment scripts that may reference or instantiate the specific IOCs associated with Stealer as part of a legitimate application bundle (e.g., deploying a new CRM client).
- Filter/Exclusion: Implement an exclusion based on the user context and process name. Filter out alerts where the initiating user is a service account (e.g., DOMAIN\SCCM-Deploy-Svc) or the parent process belongs to known deployment tools (ccmexec.exe, ansible-playbook).
Scenario: Scheduled Backup Jobs Accessing Shared Network Drives
- Context: Enterprise backup solutions like Veeam Backup & Replication or Commvault run nightly jobs that traverse network shares