ThreatFox: jSpy IOCs

Hunt Hypothesis

This detection rule identifies adversary activity associated with the jSpy remote access tool by matching known Indicators of Compromise (IOCs) within Azure Sentinel logs. Proactively hunting for these signals is critical to uncover persistent threats leveraging legitimate RAS tools for lateral movement and data exfiltration before they escalate into significant security incidents.

IOC Summary

Malware Family: jSpy Total IOCs: 2 IOC Types: domain

KQL: Domain Hunt

// Hunt for DNS queries to known malicious domains
// Source: ThreatFox - jSpy
let malicious_domains = dynamic(["acocdn.com", "asecdns.com"]);
DnsEvents
| where Name has_any (malicious_domains)
| project TimeGenerated, Computer, Name, IPAddresses, QueryType
| order by TimeGenerated desc

Required Data Sources

References

• ThreatFox — jSpy

False Positive Guidance

Here are 4 specific false positive scenarios for the ThreatFox: jSpy IOCs detection rule, including targeted filters and exclusions suitable for an enterprise environment:

• Antivirus & EDR Signature Updates

  • Scenario: Enterprise Endpoint Detection and Response (EDR) agents like CrowdStrike Falcon, Microsoft Defender for Endpoint, or Carbon Black frequently download threat intelligence feeds containing jSpy indicators. When these agents update their local databases, they may instantiate processes that match the rule’s IOCs (e.g., specific file hashes or network connections to known jSpy C2 domains) during scheduled maintenance windows.
  • Filter/Exclusion: Create a detection exclusion for processes running under the EDR service accounts (e.g., svc-falcon, MsMpEng) and exclude traffic originating from the internal update servers of these specific vendors. Additionally, whitelist known jSpy hash signatures that are part of the standard vendor feed updates.

• Scheduled Enterprise Backup Jobs

  • Scenario: Automated backup solutions such as Veeam Backup & Replication, Rubrik, or Commvault often utilize agents that scan and transfer data to cloud repositories. If jSpy IOCs include specific file extensions (e.g., .jar, .exe) or network ports used by these backup agents, the rule may trigger when the nightly job executes a large-scale data synchronization task involving similar artifacts.
  • Filter/Exclusion: Implement a time-based filter to suppress alerts during known maintenance windows (e.g., 02:00 – 04:00 UTC) for processes named VeeamAgent.exe or rubrik-agent. Alternatively, exclude the specific IP ranges of the backup repository servers and the service accounts running these jobs from the detection logic.

• Software Deployment & Patching Workflows

  • **Scenario