Remcos

Overview

Remcos (an acronym for 'Remote Control & Surveillance') is a feature-rich, commercial Remote Access Trojan first released in 2016 by Italian software developer Francesco Balestrazzi through his Germany-registered commercial entity 'BreakingSecurity'. Although marketed openly as a dual-use administrative utility, Remcos was rapidly adopted by cybercrime syndicates and advanced persistent threat (APT) actors as a primary tactical espionage and intrusion framework. Remcos provides comprehensive remote surveillance and administrative domination over compromised endpoints: it captures keystrokes, records microphone audio and webcam feeds, steals credentials from web browsers and email clients, executes reverse proxies, and deploys secondary malware. Remcos has been the subject of numerous emergency cybersecurity advisories issued by the US Cybersecurity and Infrastructure Security Agency (CISA) and the FBI (notably Alert AA20-049A and AA22-110A), documenting its widespread deployment by nation-state actors (including UAC-0056 / SaintBear) and financial cybercrime syndicates in weaponized phishing campaigns delivering Microsoft Office documents exploiting CVE-2017-0199 and CVE-2017-11882.

Known aliases

Threat reports may refer to this family under multiple names:

• Remcos
• Remcos RAT
• RemcosRAT
• Backdoor.Win32.Remcos
• RAT.Remcos

Threat Actor Attribution

Attribution is probabilistic, not a science. Each link below states its confidence level and the evidence behind it.

• Francesco Balestrazzi (BreakingSecurity) / Global APT & Cybercrime Operators (CISA Alert AA22-110A) High confidence
  Basis: Authored and commercialized by Francesco Balestrazzi via BreakingSecurity. Highlighted in joint US CISA and FBI alerts as one of the most widely weaponized commercial RATs deployed in global espionage and cybercrime campaigns. [source]

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Known Derivatives & Downstream Variants: Remcos V1.7 · Remcos V2.X · Remcos V3.X · Remcos Professional V4.X

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:

• T1056.001: Implement Endpoint Detection and Response (EDR) to monitor for suspicious API calls related to keystroke interception. Enforce Multi-Factor Authentication (MFA) to render stolen passwords useless.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1113: Monitor for frequent or unauthorized screen captures or clipboard reads. Restrict background applications from accessing desktop APIs.
• T1125: Restrict access to local camera or microphone APIs. Utilize endpoint protection that monitors hardware access.

MITRE D3FEND™ Defensive Countermeasures

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

Exploited Vulnerabilities (CVEs)

This malware family is documented weaponizing the following common vulnerabilities and exposures:

• CVE-2017-0199 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).
• CVE-2017-11882 — In-depth exploitation analysis and catalog intelligence (NIST NVD ↗).

Command & Control (C2) and Network Profile

How this family talks to its operators. C2 traffic can often identify a family even when its code and configuration are hard to analyse. Ports and patterns are historical and change between campaigns, so use them as hunting leads rather than block-only rules.

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 4a242f36f6d895f462ebc8375e87a26f8303f26cfb16954316d2ca0190abf0c1
• e236526eb8fb386f6f1c4e97669e4f5530ecdfce9a2ffb38ab8fa176df2c75a4

Delivery vectors

• Phishing emails disguised as purchase orders, tax invoices, or shipping updates with weaponized Word documents (CVE-2017-11882)
• ISO/IMG disk images containing VBScript, AutoIt, or JavaScript downloaders dropping obfuscated Remcos executables

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run entry pointing to staged executable in %APPDATA%
• Process hollowing into legitimate Windows binaries including svchost.exe, cmd.exe, or msiexec.exe

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_REMCOS_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Remcos"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "remcos" ascii wide nocase
        $s2 = "remcos" ascii wide nocase
        $s3 = "remcos rat" ascii wide nocase
        $s4 = "remcosrat" ascii wide nocase
        $s5 = "backdoor.win32.remcos" ascii wide nocase
        $s6 = "rat.remcos" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Remcos (Rat) Execution & Triage
id: 22ecacdd-068c-5579-b25e-27367cf1aa75
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Remcos malware family. Detects unauthorized persistence creation via Windows
  Registry Run keys, scheduled tasks, and privilege escalation indicative of RAT installations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/remcos
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-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.rat
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1055_012
- attack.t1056_001
- attack.t1113
- attack.t1125
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \reg.exe
    - \schtasks.exe
    - \cmd.exe
    - \powershell.exe
    CommandLine|contains:
    - \CurrentVersion\Run
    - /create /tn
    - bypass -enc
    - net user /add
    - net localgroup administrators
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_REMCOS_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Remcos 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 = "remcos" 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 isolate the compromised host from internal LAN and WAN environments to cut off interactive remote shell sessions established by Remcos.
2. Inspect active socket listeners and outbound established network connections ('netstat -ano') to identify and sever covert TCP/UDP channels used by Remcos.
3. Scan Windows Services, Scheduled Tasks, and Startup folders to locate and eliminate persistent backdoor listeners configured by Remcos.
4. Invalidate all active VPN profiles, local administrator credentials, and session tokens that may have been harvested by the Remcos operator.
5. Re-image the affected host using a validated golden image prior to reconnecting it to enterprise network segments.

What to Avoid

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

1. Do not attempt to interact with or send messages through the Remcos remote terminal, as this alerts the attacker and may cause them to execute destructive anti-forensic commands.
2. Avoid relying solely on static file signatures, as Remcos payloads frequently execute reflectively in memory without writing binaries to disk.

References & External Analysis

• CISA Alert AA22-110A - Threat Actors Abuse Remcos RAT
• MITRE ATT&CK - Remcos (S0332)
• FBI Flash Alert - Commercial RAT Exploitation
• Search "remcos" on VirusTotal (External Analysis)
• Search "remcos" on Any.Run (Sandbox Sandbox)
• Search "remcos" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Rat)

Explore other documented threats in the same operational category:

• Spygate
• Wabot
• Hupigon
• Apocalypse_Rat
• Bladabindi
• Pcclient
• Lost_Door
• Bandook

Machine-readable

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