ThreatFox: NetWire RC IOCs

Hunt Hypothesis

This hunt targets the presence of NetWire Remote Control IOCs, which indicate an adversary has established a covert channel for remote access and command execution. Proactively hunting for these indicators in Azure Sentinel is critical to identify compromised endpoints before the attacker leverages the remote control tool for lateral movement or data exfiltration.

IOC Summary

Malware Family: NetWire RC Total IOCs: 3 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(["5f8208c4790ca7b7aa199cf9ae09933bef089e0f86df853b17b59c14e7aa3fab", "fe41aa1fce4a41a11da253af51497ed86774fefb", "3f924a568b81cddd3f7fdbcc19721edf"]);
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

• Legacy Remote Support Tooling in Field Operations: Field engineers or IT support staff may use NetWire RC (or its underlying NetWire protocol) as a lightweight, cross-platform remote control solution for troubleshooting hardware or software issues on client machines, especially in environments where standard RDP or VNC is blocked by firewalls.

  • Filter/Exclusion: Exclude processes named netwire.exe or nwrc.exe when the parent process is a known remote support agent (e.g., teamviewer.exe, anydesk.exe, or ultravnc.exe) or when the process is launched from a specific “Remote Support” directory (e.g., C:\Program Files\RemoteSupport\).

• Scheduled Maintenance Jobs for Non-Standard Ports: In environments where standard remote desktop ports (3389) are heavily monitored or restricted, administrators may configure scheduled tasks to launch NetWire RC on non-standard ports for periodic connectivity checks or automated backups of remote systems.

  • Filter/Exclusion: Exclude instances where the process is initiated by Task Scheduler (taskschd.exe) or svchost.exe (if running as a service) and the command line arguments include a specific port number (e.g., :45678) that matches a documented internal non-standard remote access port.

• Development and Testing Environments: Developers or QA engineers may use NetWire RC to test remote connectivity, load balancing, or network segmentation rules in isolated lab or staging environments.

  • Filter/Exclusion: Exclude processes running on hosts tagged with “Dev”, “Staging”, or “Lab” in your asset inventory or CMDB, or exclude processes where the working directory is within a development path (e.g., C:\Users\<dev_user>\Projects\, D:\Lab\, or /opt/dev/).

• **Third