ThreatFox: Unknown Stealer IOCs

Hunt Hypothesis

This hunt hypothesis targets adversary behavior where the Unknown Stealer malware executes data exfiltration activities by leveraging five specific Indicators of Compromise (IOCs) to identify compromised endpoints. The SOC team should proactively hunt for these signals in Azure Sentinel to rapidly detect early-stage infections and mitigate potential credential theft before lateral expansion occurs across the cloud environment.

IOC Summary

Malware Family: Unknown Stealer Total IOCs: 5 IOC Types: domain, ip:port

KQL: Ip Hunt

// Hunt for network connections to known malicious IPs
// Source: ThreatFox - Unknown Stealer
let malicious_ips = dynamic(["130.61.68.232"]);
CommonSecurityLog
| where DestinationIP in (malicious_ips) or SourceIP in (malicious_ips)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, DeviceAction, Activity
| order by TimeGenerated desc

KQL: Ip Hunt Device

// Hunt in Defender for Endpoint network events
let malicious_ips = dynamic(["130.61.68.232"]);
DeviceNetworkEvents
| where RemoteIP in (malicious_ips)
| project Timestamp, DeviceName, RemoteIP, RemotePort, InitiatingProcessFileName, ActionType
| order by Timestamp desc

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - Unknown Stealer
let malicious_domains = dynamic(["pokese.pro", "great-fade.sbs", "bkscndcloud.beer", "cashorix.xyz"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — Unknown Stealer

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: Unknown Stealer IOCs detection rule, including suggested filters and exclusions tailored for an enterprise environment:

• Endpoint Protection Scheduled Scans (CrowdStrike/Falcon)

  • Scenario: The enterprise Endpoint Detection and Response (EDR) agent performs a scheduled deep scan of the C:\Users\Public directory. During this process, the EDR’s heuristic engine generates temporary IOCs for known benign file hashes that happen to match the “Unknown Stealer” pattern in the ThreatFox feed but are actually part of the standard OS update package or legitimate third-party software (e.g., Adobe Reader updates).
  • Filter/Exclusion: Create an exclusion rule based on Process Name and Parent Process. Exclude alerts where ProcessName is CSPService.exe (CrowdStrike) or McShield.exe (McAfee) AND the ParentProcessName matches the specific EDR service scheduler. Additionally, whitelist file paths containing \Program Files\Adobe\Acrobat Reader DC\.

• IT Asset Management Inventory Agents

  • Scenario: The IT Operations team deploys a scheduled inventory job using Microsoft SCCM (Configuration Manager) or ** Lansweeper**. These agents actively enumerate installed software and network shares, creating temporary IOCs for executable files located in shared administrative folders (e.g., \\FileServer\IT_Deployments\Stealer_Tools). The detection logic flags these legitimate deployment artifacts as potential “Unknown Stealer” activity due to their file signatures.
  • Filter/Exclusion: Implement a filter that excludes events originating from specific User Accounts associated with the asset management service (e.g., svc-sccm-agent or admin-inventory). Furthermore, exclude network paths starting with `\FileServer\IT_Deployments\