ThreatFox: SmartApeSG IOCs

Hunt Hypothesis

This hunt detects adversary activity involving specific indicators of compromise (IOCs) linked to the SmartApeSG threat actor to identify potential early-stage intrusions or lateral movement within the network. Proactively hunting for these IOCs in Azure Sentinel is critical because it enables the SOC team to rapidly isolate and investigate high-severity threats before they escalate into broader data breaches or system compromises.

IOC Summary

Malware Family: SmartApeSG Total IOCs: 4 IOC Types: domain, url

KQL: Domain Hunt

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

KQL: Url Hunt

// Hunt for access to known malicious URLs
// Source: ThreatFox - SmartApeSG
let malicious_urls = dynamic(["https://chestnutstanza.top/realm/health-service", "https://chestnutstanza.top/realm/acl-controller.js"]);
UrlClickEvents
| where Url has_any (malicious_urls)
| project Timestamp, AccountUpn, Url, ActionType, IsClickedThrough
| order by Timestamp desc

Required Data Sources

References

• ThreatFox — SmartApeSG

False Positive Guidance

Here are 5 specific false positive scenarios and corresponding filters for the ThreatFox: SmartApeSG IOCs detection rule in an enterprise environment:

• Scenario: The Security Operations Center (SOC) team runs a manual threat intelligence feed update using Microsoft Defender for Endpoint or CrowdStrike Falcon, which automatically ingests the SmartApeSG IOC list into the local policy engine. This triggers the rule as the system queries the IOCs against its internal database, mimicking an active scan rather than a malicious event.

  • Suggested Filter: Exclude events where the Process Name matches known SIEM/EDR management agents (e.g., DefenderService.exe, FalconSensor.exe) and the User Account is a dedicated service account like svc-threat-intel or admin-soc.

• Scenario: A scheduled nightly backup job utilizing Veeam Backup & Replication or Commvault performs a deep scan of the file system to verify integrity. The backup engine’s scanning module explicitly checks against known threat indicators, including the SmartApeSG signatures, causing the detection logic to fire during the window between 02:00 and 04:00 UTC.

  • Suggested Filter: Create a time-based exclusion for events occurring between 01:30 and 05:00 on weekdays where the Parent Process Name is identified as VeeamTransportService.exe or CommServeAgent.exe.

• Scenario: The IT Operations team executes a quarterly vulnerability assessment using Tenable Nessus or Qualys, which includes a specific module for “Advanced Threat Intelligence Correlation.” During the scan, the tool actively resolves and validates the 4 SmartApeSG IOCs against the network inventory, generating detection alerts that are actually part of the assessment workflow. *