A recent cyber threat named Neptune RAT has emerged as a rising concern for Windows users, targeting sensitive data and exhibiting advanced malicious capabilities.
CYFIRMA researchers have identified the latest version of this Remote Access Trojan (RAT), revealing alarming details about its distribution, functionality, and impact on compromised systems.
Technical Overview of Neptune RAT
Neptune RAT is a sophisticated malware developed in Visual Basic .NET. It is distributed across platforms such as GitHub, Telegram, and YouTube, often marketed as the “Most Advanced RAT.”
The software is available without source code, but its obfuscated executable files make analysis challenging for cybersecurity experts.

PowerShell Command Exploitation
Neptune RAT v2 employs direct PowerShell commands such as:
- Invoke-RestMethod (irm): Facilitates downloading malicious scripts from the internet.
- Invoke-Expression (iex): Executes the downloaded scripts.
These commands enable the malware to download and run encoded payloads hosted on platforms like catbox.moe, which are saved in the victim’s AppData folder for execution.
Malicious Features of Neptune RAT
Neptune RAT is a multi-feature malware capable of:
- Password grabbing across 270+ applications, including browsers such as Chrome, Opera, and Brave.
- Crypto clipper functionalities, altering cryptocurrency wallet addresses on the clipboard.
- Ransomware deployment through internal modules like Ransomware.dll.
- Live desktop monitoring for real-time victim surveillance.
- System destruction, including rewriting the Master Boot Record (MBR).
- Antivirus disablement and registry manipulation for persistence.
DLL-Based Modular Approach
The malware uses several malicious DLL files for targeted tasks:
- Ransomware.dll encrypts files and demands Bitcoin payments for decryption.
- Chromium.dll steals passwords stored in browser profiles.
- BlockAntivirus.dll disables security measures to evade detection.
Advanced obfuscation makes Neptune RAT resistant to analysis:
- Arabic Characters and Emojis: Malware strings are replaced with Arabic text, complicating reverse engineering.
- High Entropy Heaps: Critical data, such as encryption keys, are stored in heaps like “User String Heap(7),” identified with high entropy values exceeding 7.
- String Encryption: Custom encryption/decryption methods further obscure internal operations.


Persistence and Anti-Analysis Techniques
Neptune RAT incorporates multiple persistence mechanisms:
- Task Scheduler: Creates hidden tasks to run malware periodically.
- Registry Keys Modification: Adds entries to the Run key in HKEY_CURRENT_USER for automatic execution at system startup.
In addition, the RAT employs virtual machine detection through queries to the Win32_ComputerSystem class.
If the malware detects environments such as VMware or VirtualBox, it disables itself to avoid security researchers intercepting its actions.

Dynamic Analysis Findings
Upon execution, Neptune RAT manipulates the victim’s system by:
- Copying itself to the Roaming folder in AppData.
- Registering itself in the Windows Registry Run key for sustained infection.
- Automating tasks through the schtasks.exe utility to maintain a continuous connection to the attacker’s server.
The malware’s ransomware payload, once launched, encrypts all accessible files and changes their extensions to “.ENC.”
The victim is presented with instructions for ransom payment via a desktop file named “How to Decrypt My Files.html.”

The developer of Neptune RAT actively markets the malware through GitHub and personal websites, hinting at a more advanced paid version.
CYFIRMA traced affiliations to groups like the Freemasonry team, adding an organized layer to this threat’s distribution.
Neptune RAT is a highly potent malware with an arsenal of features that pose significant risks to both individual users and organizations.
Its ability to exfiltrate sensitive information, deploy ransomware, and maintain stealth using advanced obfuscation techniques makes it a dangerous tool for cybercriminals.
To defend against threats like Neptune RAT, users and organizations should:
- Implement robust endpoint protection and anti-malware solutions.
- Limit the use of PowerShell commands and monitor unusual requests.
- Regularly update operating systems and software to mitigate vulnerabilities.
- Employ proactive threat monitoring and detection strategies.
With its evolving features and distribution tactics, Neptune RAT exemplifies the growing sophistication of modern cyber threats.
Awareness and vigilance are critical in combating such malware and safeguarding sensitive data.
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