This hunt targets adversary behavior where malicious actors deploy the QuirkyLoader dropper to establish persistence and execute secondary payloads via three specific Indicators of Compromise (IOCs). Proactively hunting for these signatures in Azure Sentinel is critical because early detection of this loader prevents lateral movement and data exfiltration before the full malware chain activates.
Malware Family: QuirkyLoader Total IOCs: 3 IOC Types: sha256_hash, sha1_hash, md5_hash
| Type | Value | Threat Type | First Seen | Confidence |
|---|---|---|---|---|
| sha1_hash | a041d35efc838a8d88586c2ab38f3740b8f543d8 | payload | 2026-07-05 | 95% |
| md5_hash | 23938cf31c1fa4700341cab81b0f3243 | payload | 2026-07-05 | 95% |
| sha256_hash | 9df5a7b74fadadc12c289fff3f5c7f58e3893e5a36df8a287b1f69e588a7e818 | payload | 2026-07-05 | 95% |
// Hunt for files matching known malicious hashes
// Source: ThreatFox - QuirkyLoader
let malicious_hashes = dynamic(["a041d35efc838a8d88586c2ab38f3740b8f543d8", "23938cf31c1fa4700341cab81b0f3243", "9df5a7b74fadadc12c289fff3f5c7f58e3893e5a36df8a287b1f69e588a7e818"]);
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
| Sentinel Table | Notes |
|---|---|
DeviceFileEvents | Ensure this data connector is enabled |
Here are specific false positive scenarios for the ThreatFox: QuirkyLoader IOCs detection rule in an enterprise environment, along with recommended filters or exclusions:
Endpoint Protection Policy Updates via Microsoft Intune/SCCM
QuirkyLoader associated IOCs (specifically network connections to known vendor IP ranges and file hashes of the updater executable) across thousands of endpoints simultaneously, mimicking the initial infection behavior of QuirkyLoader.IntuneManagementExtension.exe, ccmexec.exe (SCCM), or MsMpEng.exe and the destination IP matches the organization’s known update server subnets or vendor CDN ranges defined in the asset inventory.Automated Patch Deployment by WSUS or Ansible
SYSTEM account with specific command lines containing keywords like /patch, update-agent, or ansible-playbook, specifically during the maintenance window (e.g., 02:00–04:00 UTC).Third-Party Backup Agent Initialization