ThreatFox: Arkei Stealer IOCs

Hunt Hypothesis

This hunt targets adversary behavior involving the execution of known Arkei Stealer indicators to identify active credential theft and data exfiltration attempts within the environment. Proactively hunting for these specific IOCs in Azure Sentinel is critical because early detection enables rapid containment before sensitive authentication tokens are compromised, thereby preventing lateral movement by threat actors.

IOC Summary

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

Type	Value	Threat Type	First Seen	Confidence
md5_hash	`5cbb51cf747cd514eb333f402e21866c`	payload	2026-07-13	95%
sha256_hash	`3b328b13d6925bb86cfa46b58586530dd14e6f0f627ec92a1f14ef162d5712ec`	payload	2026-07-13	95%
sha1_hash	`6e1561e0b51a74b01a2e0377f52ea95a38e439fb`	payload	2026-07-13	95%

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - Arkei Stealer
let malicious_hashes = dynamic(["5cbb51cf747cd514eb333f402e21866c", "3b328b13d6925bb86cfa46b58586530dd14e6f0f627ec92a1f14ef162d5712ec", "6e1561e0b51a74b01a2e0377f52ea95a38e439fb"]);
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 — Arkei Stealer

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: Arkei Stealer IOCs detection rule, along with suggested filters and exclusions tailored for an enterprise environment:

Endpoint Protection Scanning of Quarantine Archives
- Scenario: Enterprise EDR solutions (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) periodically scan their own quarantine folders. If a previously detected Arkei sample was quarantined, the EDR’s internal scanning process may generate file access events matching the Stealer’s IOCs (specifically hash matches on archived malicious files), triggering an alert despite no active threat.
- Filter/Exclusion: Exclude processes belonging to known security suites from the detection scope. Add a filter for ProcessName containing “CrowdStrike”, “Defender”, or “McAfee” AND CommandLine containing keywords like “-scan”, “-quarantine”, or “-archive”.
IT Admin Deployment of Security Updates via SCCM/Intune
- Scenario: System Administrators use Microsoft Endpoint Configuration Manager (SCCM) or Intune to push security patches. During the deployment phase, these tools often extract and execute temporary installer packages that may contain shared libraries or cryptographic signatures matching Arkei IOCs (e.g., specific DLLs used for telemetry). This is particularly common when deploying updates to the “Security Tools” category.
- Filter/Exclusion: Whitelist execution paths associated with deployment agents. Create an exclusion rule where ParentProcessName equals “ccmexec.exe” or “IntuneManagementExtension.exe” AND the file path resides within the standard software distribution directory (e.g., C:\Windows\CCMCache\).
Scheduled Antivirus Full System Scans
- Scenario: Scheduled nightly full system scans performed by legacy AV solutions (such as Symantec Endpoint Protection