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 our technical analysis hubs and the official 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.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_RADMIN_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Radmin"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "radmin" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Radmin (Ransomware) Execution & Triage
id: f850f060-af6d-57f0-ae22-300156df1b23
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Radmin malware family. Detects volume shadow copy deletion, boot status
  tampering, and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/radmin
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1105
- attack.t1219
- attack.t1543_003
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \vssadmin.exe
    - \wmic.exe
    - \wbadmin.exe
    - \bcdedit.exe
    CommandLine|contains:
    - delete shadows
    - shadowcopy delete
    - resize shadowstorage
    - recoveryenabled no
    - ignoreallfailures
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: critical

rule MALWARE_WIN_RADMIN_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Radmin tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "radmin" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

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)
• Search "radmin" on Any.Run (Sandbox Sandbox)
• Search "radmin" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Crusis
• Zzinfor
• Detplock
• Graz
• Necne
• Cyfin
• Smearpasse
• Oztar

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/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.