Radmin

Overview

RemoteAdmin:Win32/Radmin (Remote Administrator) is a legitimate, commercial remote control software application. However, because it provides full, interactive GUI access, file transfer capabilities, and operates silently in the background (as a Windows Service), it is frequently weaponized by advanced threat actors (APTs) and ransomware cartels. They deploy it as a stealthy, persistent backdoor to maintain access and facilitate lateral movement across a compromised network (`T1219`).

Understanding Radmin (Abused Legitimate Tools)
To an end-user, Radmin operates invisibly if configured as a service by an attacker. For a security team, the unauthorized presence of Radmin is a 'Code Red'. Like AnyDesk or TeamViewer, it is a classic 'Living off the Land' tool. Because the binaries (`rserver3.exe`, `FamImaf.sys`) are digitally signed by a legitimate software company (Famatech), many antivirus engines will ignore them by default, allowing the attacker unfettered access.

Execution and Abuse Mechanics
Attackers do not typically use Radmin for initial access. It is deployed post-compromise (`T1105`). Once an attacker has administrative rights on a machine (e.g., via compromised credentials), they silently install the Radmin Server component (`T1543.003`). They configure it to hide its system tray icon, set a strong custom password, and open a listening port (default is TCP 4899). The attacker can now connect to this machine from anywhere, completely bypassing standard EDR behavioral checks, as the remote activity appears to be legitimate administrative work.

Indicators of Compromise & Impact
The impact is total, interactive control of the host and a launchpad for lateral movement. Host-based IoCs include the presence of `rserver3.exe`, the associated Famatech driver files, and the creation of the 'Radmin Server' Windows service. EDR should monitor for the installation of these binaries in unusual directories (e.g., `%Temp%`). Network IoCs include inbound connections on TCP port 4899 (or a custom configured port) originating from outside the recognized corporate admin subnets.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_RADMIN {
    meta:
        description = "Detects Radmin (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "radmin" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Radmin Activity
id: 5dd53a59c34c9cbd48ef3fb50b0873a1
status: experimental
description: Detects generic indicators of the radmin malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*radmin*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Immediately terminate the `rserver3.exe` process and isolate the machine to sever the attacker's interactive connection.
2. Assume the attacker has compromised all credentials on the machine and potentially mapped the internal network; initiate a broad incident response.
3. Use EDR to hunt for the presence of `rserver3.exe` and its associated registry keys (`HKLM\SOFTWARE\Radmin`) across the entire enterprise to find lateral movement.
4. Block TCP port 4899 (and investigate any custom ports discovered in the registry config) at the internal network boundaries.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume Radmin is a false positive just because it is a legitimate tool; if your IT department doesn't use it, it is a severe threat.
2. Avoid simply uninstalling the software; you must investigate what the attacker did while they had interactive access (e.g., deployed ransomware, dumped credentials).

References & External Analysis

• Search "radmin" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Lunam
• Genericrxcr
• Recex
• Ursumdt
• Artel

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/radmin.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.