ThreatFox: Zeus IOCs | SOC Hunt Feed

Hunt Hypothesis

This hunt targets adversary behavior where the Zeus banking Trojan injects malicious code into web browsers to intercept and manipulate sensitive financial transactions. Proactive hunting in Azure Sentinel is critical because early detection of these specific IOCs allows the SOC team to isolate compromised endpoints before significant data exfiltration or fraudulent transaction execution occurs.

IOC Summary

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

Type	Value	Threat Type	First Seen	Confidence
sha256_hash	`8c50b7a1ddc3e95f1106e7515fb36811c298257135b3b376c82bee04391e6cfa`	payload	2026-07-14	95%
sha1_hash	`c22abd6f58b80af730abad42dde43979de469117`	payload	2026-07-14	95%
md5_hash	`0a15d395369645b594180541e13f05d7`	payload	2026-07-14	95%

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - Zeus
let malicious_hashes = dynamic(["8c50b7a1ddc3e95f1106e7515fb36811c298257135b3b376c82bee04391e6cfa", "c22abd6f58b80af730abad42dde43979de469117", "0a15d395369645b594180541e13f05d7"]);
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 — Zeus

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: Zeus IOCs detection rule in an enterprise environment, along with recommended filters or exclusions:

Scheduled Antivirus Definition Updates via GPO
- Scenario: The enterprise uses a Group Policy Object (GPO) to push daily definition updates from Symantec Endpoint Protection or CrowdStrike. These updates often download large signature packages that contain embedded scripts and HTTP requests matching the Zeus IOCs’ communication patterns with update servers, triggering alerts on endpoint workstations.
- Filter/Exclusion: Create an exclusion rule for traffic originating from specific internal IP ranges (e.g., 10.x.x.x or 192.168.x.x) destined for known vendor update endpoints (e.g., *.symantec.com, *.crowdstrike.com). Additionally, exclude the specific process hash of the AV updater service (e.g., Symantec Antivirus Update Service.exe) from the detection scope.
Automated Browser Extension Deployment by IT Admins
- Scenario: The IT department utilizes Microsoft Intune or Jamf Pro to silently deploy and update security extensions (such as Cisco Umbrella Roaming Client or Norton Safe Web) across all user browsers. These tools inject code into the browser’s rendering engine to filter web traffic, a behavior that closely mimics Zeus’s browser injection mechanism for transaction manipulation.
- Filter/Exclusion: Exclude alerts where the source process is identified as the deployment agent (e.g., Microsoft Intune Management Extension or JamfProAgent) and the target application is a known enterprise browser (Chrome, Edge). Implement a whitelist for the specific SHA-256 hashes of these approved extensions.
Internal Web Proxy SSL Inspection Traffic