ThreatFox: NetWire RC IOCs

Hunt Hypothesis

This hunt detects adversary activity involving the specific indicators of compromise (IOCs) linked to the NetWire Remote Access Trojan, which is known for establishing persistent backdoors and exfiltrating sensitive data from compromised endpoints. A SOC team should proactively hunt for these IOCs within Azure Sentinel to identify early-stage infections that may evade standard signature-based detection, thereby preventing potential lateral movement and data theft before they escalate into significant incidents.

IOC Summary

Malware Family: NetWire RC Total IOCs: 15 IOC Types: sha256_hash, sha1_hash, md5_hash

KQL: Hash Hunt

// Hunt for files matching known malicious hashes
// Source: ThreatFox - NetWire RC
let malicious_hashes = dynamic(["87ac54897c3cb1a2b15f46c5897254f2579e529e", "cdba3f620f58b3283c37ad512452a9d7", "a86215689dcc155290c3bbf9cf9e0da4d82681ffccab1a490965805ba26d7d76", "b5248924bb215076323efa59a05a011d6199bbe1", "626e45681bd083f5f85acd0f6aefe5bc", "920f619ff80cdf2532571d9a55fe7c4ec79ce02f", "476453e63cf65c3fbe54f9b2cb3cc649", "375b42096406eed802c5470175c1b1a9f0a49933b17109cfbfb734593d1acd26", "edbc21717aa9547c84daafe4780bc848b1876d47", "5a5171a49e704db4a7c0ac25c6713812", "15f9f4389d34c8ffdc2ea7de5a4827e718b1d14e8a7b67b76bf8fc2486b5caff", "395cb23969206c1a5fabe746a0a891835d4c87e6", "583614371adddbcaf7f6c087479c77ab", "1a2f081585e05540a72ceb36178f9549ff5bc3c6505fddb6565b887aa55f54a3", "8ab5ad6e0c8b4cc906d162eb529b417b0d10a140bf295fb963cb63e70173c795"]);
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

References

• ThreatFox — NetWire RC

False Positive Guidance

Here are specific false positive scenarios and corresponding exclusions for the ThreatFox: NetWire RC IOCs detection rule:

• Scenario: The enterprise’s endpoint protection suite (e.g., CrowdStrike Falcon or Microsoft Defender for Endpoint) performs a scheduled daily definition update that triggers network connections to the vendor’s cloud infrastructure, which overlaps with NetWire RC telemetry endpoints.

  • Filter/Exclusion: Create an exclusion rule based on the specific process name of the EDR agent (e.g., FalconSensor.exe or MsMpEng.exe) and restrict the scope to the known update schedule window (e.g., 02:00–04:00 AM local time).

• Scenario: The IT Operations team utilizes a centralized patch management tool like SCCM (System Center Configuration Manager) or Intune to push configuration scripts, which initiates background network traffic to NetWire RC repositories for license validation and policy synchronization.

  • Filter/Exclusion: Exclude alerts originating from the specific Service Account used by the patching engine (e.g., DOMAIN\PatchAdmin) running on the dedicated Patch Server host, specifically when the destination port matches standard management ports (443 or 80).

• Scenario: A legacy business intelligence dashboard (e.g., Tableau Server or Power BI Gateway) is configured to pull external data feeds via a scheduled job that utilizes NetWire RC as an intermediate proxy for secure data ingestion.

  • Filter/Exclusion: Implement a whitelist entry for the specific Scheduled Task name (e.g., Tableau_DataSync) and exclude traffic where the source IP belongs to the BI Server subnet, provided the connection duration is consistent with historical baselines (e.g., < 5 minutes).

• Scenario: The organization’s SIEM or Log Aggregation platform (such as Splunk Heavy Forwarders or Elastic Beats) periodically sends