Remcos RAT
By eSentire Threat Response Unit (TRU)
Archived: 2026-04-05 19:45:53 UTC
Adversaries don’t work 9-5 and neither do we. At eSentire, our 24/7 SOCs are staffed with Elite Threat Hunters
and Cyber Analysts who hunt, investigate, contain and respond to threats within minutes.
We have discovered some of the most dangerous threats and nation state attacks in our space – including the
Kaseya MSP breach and the more_eggs malware.
Our Security Operations Centers are supported with Threat Intelligence, Tactical Threat Response and Advanced
Threat Analytics driven by our Threat Response Unit – the TRU team.
In TRU Positives, eSentire’s Threat Response Unit (TRU) provides a summary of a recent threat investigation. We
outline how we responded to the confirmed threat and what recommendations we have going forward.
Here’s the latest from our TRU Team…
What did we find?
Remcos (Remote Control & Surveillance Software) was identified in a customer environment in the legal
services industry.
Remcos is a malicious remote access tool (RAT) marketed as a legitimate remote administration tool which
can be purchased for between €58-399.
The tool can be used to control the system, capture keystrokes, webcam images, screen captures,
and passwords (among other capabilities).
Version 3.3.2 Pro was identified in this incident.
The infection vector for Remcos was a password-protected, macro-enabled Excel file named “remittance
advice.xlsm”.
Once opened, PowerShell is executed to retrieve a remote script (edi.vbs/firewall.vbs) from
hxxp://lbl[.]support.
The script fetches additional components, enables persistence via registry run key and ultimately
executes Remcos within a legitimate Windows process.
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Figure 1 Online purchasing form for Remcos
Figure 2 Process tree showing execution stages
How did we find it?
BlueSteel, our machine-learning powered PowerShell classifier, identified PowerShell commands executed
by Remcos RAT
MDR for Endpoint identified secondary execution phases.
What did we do?
Our team of 24/7 SOC Cyber Analysts isolated the host and worked with the customer to remediate.
What can you learn from this TRU positive?
Remcos provides an attacker with nearly full control of the compromised system, so rapid identification
and removal is critical.
Remcos stores captured information in the following files and folders:
%APPDATA%\rem\logs.dat (captured keystrokes)
%APPDATA%\Screenshots
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%APPDATA%\MicRecords
Unfortunately, antivirus detection for the macro-enabled Excel document is minimal since password-protected documents can be used to evade link and attachment inspection.
As of January 18th, 2022 only two vendors have identified it on VirusTotal.
Recommendations from our Threat Response Unit (TRU) Team:
Employ email filtering and protection measures.
Block or quarantine email attachments such as EXEs, Password-Protected ZIPs, Javascript, and
VisualBasic scripts.
Implement anti-spoofing measures such as DMARC and SPF.
Employ an MFA solution to reduce impact of compromised credentials.
Train users to identify and report suspicious emails.
Protect endpoints against malware
Ensure antivirus signatures are up-to-date.
Use a Next-Gen AV (NGAV) or Endpoint Detection and Response (EDR) product to detect and
contain threats.
Limit or disable macros across the organization. See UK's National Cyber Centre guidance on
Macro Security.
Ask Yourself…
Can my team prevent emails containing encrypted malicious documents from reaching users?
Does my team have endpoint monitoring in place to identify malicious documents which bypass email
controls?
Indicators of Compromise
Type Value Note
File
(SHA256)
50f2ff7d96392fcfe6ed57a1ff71ae9c87a1346ff3694173a255b67e9ff8a208 firewall.vbs
File
(SHA256)
abf8ada022fce92c24e0aead4f1b1ae8991002130bbbc4335f3381972683b400
Remittance
Advice.xlsm
Domain eter101[.]dvrlists[.]com Remcos C2
Domain eter103[.]dvrlists[.]com Remcos C2
Domain lbl[.]support Hosts
firewall.vbs and
other
components
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used during
execution
If you’re not currently engaged with a Managed Detection and Response provider, we highly recommend you
partner with us for security services in order to disrupt threats before they impact your business.
Want to learn more? Connect with an eSentire Security Specialist
To learn how your organization can build cyber resilience and prevent business disruption with eSentire’s Next
Level MDR, connect with an eSentire Security Specialist now.
GET STARTED
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ABOUT ESENTIRE’S THREAT RESPONSE UNIT (TRU)
The eSentire Threat Response Unit (TRU) is an industry-leading threat research team committed to helping your
organization become more resilient. TRU is an elite team of threat hunters and researchers that supports our 24/7
Security Operations Centers (SOCs), builds threat detection models across the eSentire XDR Cloud Platform, and
works as an extension of your security team to continuously improve our Managed Detection and Response
service. By providing complete visibility across your attack surface and performing global threat sweeps and
proactive hypothesis-driven threat hunts augmented by original threat research, we are laser-focused on defending
your organization against known and unknown threats.
 Back to blog
Take Your Cybersecurity Program to the Next Level with eSentire MDR.
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BUILD A QUOTE
in this blog
What did we find?How did we find it?What did we do?What can you learn from this TRU positive?
Recommendations from our Threat Response Unit (TRU) Team:
Source: https://www.esentire.com/blog/remcos-rat
https://www.esentire.com/blog/remcos-rat
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