ThreatFox: BlankGrabber IOCs

Hunt Hypothesis

This hunt hypothesis targets adversaries utilizing the BlankGrabber malware to stealthily exfiltrate sensitive credentials and other critical data from the environment. Proactively hunting for these specific IOCs within Azure Sentinel is essential to rapidly identify active data theft incidents before significant credential compromise occurs.

IOC Summary

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

Type	Value	Threat Type	First Seen	Confidence
md5_hash	`f605e830329bcb2d6f7b9dbdea4f75b8`	payload	2026-08-02	95%
sha256_hash	`46268916a2daa6d1af68366ec1baf9bb2514a4486395288c9118019f1f49fc32`	payload	2026-08-02	95%
sha1_hash	`ea16b84b1479edaa6b359525a8299ed3b6f2c958`	payload	2026-08-02	95%

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - BlankGrabber
let malicious_hashes = dynamic(["f605e830329bcb2d6f7b9dbdea4f75b8", "46268916a2daa6d1af68366ec1baf9bb2514a4486395288c9118019f1f49fc32", "ea16b84b1479edaa6b359525a8299ed3b6f2c958"]);
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 4 specific false positive scenarios for the ThreatFox: BlankGrabber IOCs detection rule, along with targeted exclusion strategies tailored for an enterprise environment:

Scenario: Automated Backup and Archiving Jobs
- Context: Enterprise backup solutions like Veeam, Commvault, or Rubrik frequently initiate large data transfer jobs during off-hours. These agents often connect to cloud storage buckets (e.g., AWS S3, Azure Blob) using credentials that may match BlankGrabber’s known IOCs regarding network destination ports or specific file hashing patterns associated with exfiltration.
- Filter/Exclusion: Create a whitelist rule excluding traffic originating from the service accounts of backup agents (e.g., veeam-service, commvault-agent) and restricting the detection to non-backup windows (e.g., exclude alerts between 02:00–06:00 UTC). Additionally, filter out destination IPs belonging to known cloud storage CIDR blocks.
Scenario: IT Asset Management & Software Deployment
- Context: Tools like Microsoft Endpoint Configuration Manager (SCCM) or Jamf Pro regularly push software updates and inventory data from endpoints to central servers. The “stealing” behavior of BlankGrabber can mimic the bulk upload of hardware inventory logs, credential caches, and patch compliance reports generated by these deployment agents.
- Filter/Exclusion: Exclude processes running under the specific executable names ccmsetup.exe (SCCM) or jamfagentd where the destination is an internal management server IP range. Implement a filter that ignores alerts where the source process has a valid digital signature from Microsoft or Jamf Software, Inc.
Scenario: SIEM Log Forwarding and Telemetry Ingestion
- Context: Security Information and Event Management (SIEM) platforms