Beware of Weaponized TeamViewer Installer that Delivers njRAT

Threat actors relying on legitimate, well-known software TeamViewer for exploitation has been a very common scenario.

There have been several cases where threat actors used well-known software to deliver malware to the victims.

Similarly, a recent report from Cyble Research & Intelligence Labs stated that the most popularly used remote desktop support software, “TeamViewer” has been exploited by threat actors to deliver njRAT malware.

Other software that was delivering njRAT malware include Wireshark, Process Hacker, etc.,

njRAT is a remote access trojan that can perform keylogging, password stealing, data exfiltration, accessing webcams, and microphones, downloading additional files, and many others.

It was first discovered in 2012 and was attacking organizations in Middle Eastern nations. 

Weaponized TeamViewer Installer

The Initial level of compromise for njRAT involves traditional methods like phishing campaigns, cracked software on file-sharing websites, and drive-by downloads. In addition to this, the malware is now being distributed via trojanized applications.

njRAT malware dropped on the Windows Folder (Source: Cyble)

Once the malware is executed, it drops two files on the C:\Windows folder in which, one of them is the njRAT malware.

The Installer then triggers the malware “TeamViewer Starting.exe” and eventually launches the legitimate “teamviewer.exe” application.

During the installation of TeamViewer, njRAT simultaneously starts the installation by copying itself to the \AppData\Local\Temp folder with the name “system.exe.”

It then executes the newly dropped file, and njRAT creates a mutex.

Post Exploitation and Persistence

njRAT modifies the “SEE_MASK_NOZONECHECKS” environment variable in Windows, which prevents security warning prompts or dialog boxes from being presented to the user, thereby operating without any hindrance.  

njRAT autorun entries in System Registry (Source: Cyble)

Furthermore, the malware also changes the Firewall regulation to allow communications with the C2 (Command and Control) server. 

The malware creates two autorun entries in the system registry to maintain persistence in the system. 

The malware then collects information about Keystrokes, Windows OS version, service pack, webcam information, the current date, username, system architecture, and specific registry keys.

It stores all of this information in the “%appdata%/temp” folder under the filename “System.exe.tmp”.

Indicators of Compromise

Indicators Description
224ae485b6e4c1f925fff5d9de1684415670f133f3f8faa5f23914c78148fc31Trojanized Teamviewer
9b9539fec7d0227672717e126a9b46cda3315895
11aacb03c7e370d2b78b99efe9a131eb
9bcb093f911234d702a80a238cea14121c17f0b27d51bb023768e84c27f1262asystem.exe/ TeamViewer Starting.exe
b2f847dce91be5f5ea884d068f5d5a6d9140665c
8ccbb51dbee1d8866924610adb262990
hxxp://kkk[.]no-ip[.]biz C&C
Eswar

Eswar is a Cyber security content editor with a passion for creating captivating and informative content. With years of experience under his belt in Cyber Security, he is covering Cyber Security News, technology and other news.

Recent Posts

Top Ransomware Groups Target Financial Sector, 406 Incidents Revealed

Flashpoint analysts have reported that between April 2024 and April 2025, the financial sector emerged…

3 hours ago

Agenda Ransomware Group Enhances Tactics with SmokeLoader and NETXLOADER

The Agenda ransomware group, also known as Qilin, has been reported to intensify its attacks…

3 hours ago

SpyCloud Analysis Reveals 94% of Fortune 50 Companies Have Employee Data Exposed in Phishing Attacks

SpyCloud, the leading identity threat protection company, today released an analysis of nearly 6 million…

4 hours ago

PoC Tool Released to Detect Servers Affected by Critical Apache Parquet Vulnerability

F5 Labs has released a new proof-of-concept (PoC) tool designed to help organizations detect servers…

5 hours ago

Healthcare Sector Becomes a Major Target for Cyber Attacks in 2025

The healthcare sector has emerged as a prime target for cyber attackers, driven by the…

6 hours ago

SysAid ITSM Vulnerabilities Enables Pre-Auth Remote Command Execution

Security researchers have disclosed a chain of critical vulnerabilities affecting SysAid ITSM’s On-Premise solution, enabling…

6 hours ago