ThreatFox: BlankGrabber IOCs

Hunt Hypothesis

This hunt targets adversary behavior consistent with the BlankGrabber campaign by searching for specific indicators of compromise that signal active reconnaissance or data exfiltration attempts within the network. Proactively hunting these IOCs in Azure Sentinel is critical to rapidly identify and isolate potential infections before they escalate into broader lateral movement incidents, ensuring early detection of this high-severity threat actor.

IOC Summary

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

Type	Value	Threat Type	First Seen	Confidence
md5_hash	`6b5dc025587cfb9fb6d155f466dd1507`	payload	2026-07-02	95%
sha256_hash	`de42b33110544bcc3b2251d6aae89643954eba9dd697c1fb4b2316b33081d0f7`	payload	2026-07-02	95%
sha1_hash	`641dd2937fe2a05ac0f3c9c5d1358a9963023359`	payload	2026-07-02	95%

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - BlankGrabber
let malicious_hashes = dynamic(["6b5dc025587cfb9fb6d155f466dd1507", "de42b33110544bcc3b2251d6aae89643954eba9dd697c1fb4b2316b33081d0f7", "641dd2937fe2a05ac0f3c9c5d1358a9963023359"]);
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 — BlankGrabber

False Positive Guidance

Here are specific false positive scenarios for the ThreatFox: BlankGrabber IOCs detection rule, tailored for an enterprise environment:

IT Asset Management Scans via Lansweeper or SCCM
- Scenario: The enterprise IT asset management system (e.g., Lansweeper agent or Microsoft Configuration Manager) performs scheduled network discovery scans. These agents often download and execute small diagnostic scripts or configuration files that match the specific file hashes or network destinations associated with BlankGrabber, particularly if the vendor utilizes a shared CDN for their update distribution.
- Filter/Exclusion: Create an exclusion rule to whitelist traffic originating from the Lansweeper service account (e.g., DOMAIN\svc_lansweeper) and destination IPs belonging to the asset management server’s subnet, provided the process name matches LSAgent.exe.
Automated Patch Deployment via WSUS or Intune
- Scenario: During a scheduled maintenance window, the patch management system (e.g., Windows Server Update Services - WSUS) pushes a security update to endpoints. The download and installation of this update package may involve intermediate files or temporary executables that share cryptographic signatures or network artifacts with the BlankGrabber IOCs, especially if the update includes a browser-based reporting component.
- Filter/Exclusion: Exclude events where the parent process is MicrosoftEdgeUpdate.exe or WindowsUpdateAgent, and the execution time falls within the defined maintenance window (e.g., 02:00–04:00 UTC), specifically targeting the known WSUS server IP range.
Third-Party Endpoint DLP or Backup Agents
- Scenario: A Data Loss Prevention (DLP) solution like Symantec DLP or a backup agent like Veeam performs routine data indexing or policy synchronization. These agents frequently communicate with external cloud endpoints