TrojanSpy:MSIL/AgentTesla is a detection by Microsoft Defender Antivirus for a computer threat that can drop a copy of additional malware on the device. Computer users vital information is also in danger once the system is infected with this virus. It is able to collect several data points, including username, password, IP address, ISP, network setup, and computer configuration. If TrojanSpy:MSIL/AgentTesla is identified on the computer, it denotes that a more hazardous virus is about to infiltrate the system, and therefore, the user must perform an anti-virus scan immediately to avoid any further contamination.

How does it infect the computer?

TrojanSpy:MSIL/AgentTesla can reach random targets over the internet using different modules of propagation. It can carry out the attack via spam emails, malicious advertisements, bogus software updates, dubious software installers, social engineering attacks, and web injections. The latter payload carrier is running a script that automatically initiates the TrojanSpy:MSIL/AgentTesla infection through a malicious script that exploits certain software vulnerabilities in order to brute force its entry.

As soon as TrojanSpy:MSIL/AgentTesla is executed on the computer, it makes a copy of itself in the System folder of Windows. The virus also demands that the operating system run the malicious code during boot-up, which can be done by adding an entry in the Windows registry. Once TrojanSpy:MSIL/AgentTesla becomes memory resident, it can conceal its operation by masking the malicious process as legitimate, and thus, it can evade detection.

How does this malware operate?

TrojanSpy:MSIL/AgentTesla aims to collect valuable information once it infects the computer. Aside from that, this virus may also perform other malicious tasks, including the following:

  • Communicate with the remote server to download additional malware.
  • Upload the collected data to the server.
  • Update the current virus infection.
  • Disable any computer security features like antivirus and firewalls.


A computer infected with TrojanSpy:MSIL/AgentTesla may exhibit various symptoms, including unexpected system slowdowns or sluggish performance. Users may notice unauthorized access to or control over their system, with files and sensitive information being accessed or manipulated without their consent. TrojanSpy:MSIL/AgentTesla often creates backdoors for other malicious activities, leading to unexpected network traffic or unusual internet behavior. Additionally, frequent system crashes or unexplained errors may occur, indicating the presence of TrojanSpy:MSIL/AgentTesla compromising the computer’s stability and security.

Versions of TrojanSpy:MSIL/AgentTesla
Version Name Alert Level Date Added
TrojanSpy:MSIL/AgentTesla!MTB Severe Nov. 14, 2019
TrojanSpy:MSIL/AgentTesla!MSR Severe Apr. 15, 2020
TrojanSpy:MSIL/AgentTesla.AP!rfn Severe May 16, 2020
TrojanSpy:MSIL/AgentTesla is also detected as:
Avast Win32:PWSX-gen [Trj]
BitDefender Trojan.GenericKD.39629892
DrWeb Trojan.Siggen17.47124
ESET-NOD32 Win32/PSW.Agent.OJQ
F-Secure Trojan.TR/Kryptik.gnnpd
Fortinet MSIL/Kryptik.AEVQ!tr
Kaspersky HEUR:Trojan.MSIL.Crypt.gen
Malwarebytes Malware.AI.3937411490
McAfee AgentTesla-FDFR!E59C2C3D0584
Panda Trj/WLT.G
Sophos Troj/Krypt-KP

For more help

TrojanSpy:MSIL/AgentTesla belongs to a group of spyware programs that endanger the online privacy and security of computer users. To view similar threats, please browse the Trojan Spy category.

How to remove TrojanSpy:MSIL/AgentTesla?

To totally remove TrojanSpy:MSIL/AgentTesla from the computer and get rid of relevant viruses and trojans, please execute the procedures as stated on this page. Make sure that you have completely scanned the system with the suggested malware removal tools and virus scanners.

Quick Fix - Scan the PC with Combo Cleaner for Windows

Combo Cleaner is a trusted PC security and optimization tool equipped with a powerful virus and malware detection engine. This program can get rid of hazardous viruses like TrojanSpy:MSIL/AgentTesla through this procedure.

1. Download the application from the following page:

2. Save the file to your preferred location.

3. Double-click the downloaded file CCSetup.exe and install with the default settings.

CC for Windows Installation

4. At the end of the setup process, click Finish to run Combo Cleaner.

5. The tool will update the signature file, please wait for this process to complete.

6. To begin checking for threats like TrojanSpy:MSIL/AgentTesla, click on the Start Scan button. Wait for this scan to finish.

CC for Windows Start Scan

7. At the end of the scan process, click on Remove all threats to delete the TrojanSpy:MSIL/AgentTesla virus, including all malicious objects from the computer.

Free features of Combo Cleaner for Windows include Disk Cleaner, Big Files finder, Duplicate files finder, and Uninstaller. To use antivirus, privacy scanner, and to delete identified threats, users have to upgrade to a premium version.

Please continue with the succeeding removal procedures if you are comfortable manually getting rid of the virus and malicious items linked to it.

Step 1 : Start Windows in Safe Mode With Networking

Windows 10 / 11 Guide

1. Click on the Windows logo and select the Power icon when options pop up.
2. Select Restart from the options while pressing the Shift key on the keyboard.
3. Choose an Option window will appear. Select the Troubleshoot button.
4. In next window, please choose the Advanced Option.
5. On the Advanced Option window, click on Startup Settings, and then, click the Restart button to reboot the computer.
6. When Windows boots in Startup Settings, press the function key F5 or number 5 on the keyboard.

A simpler alternative for Windows 10 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.

Windows 8 Guide

1. Click the Windows Start icon in the lower left section of the screen.
2. Open the Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup, and then click on the Restart Now button.
4. Once the computer starts in the Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings, and then click the Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.

Step 2 : Run a virus scanner

To remove TrojanSpy:MSIL/AgentTesla, we suggest that you scan the infected computer with this powerful virus removal tool. It can detect and get rid of Trojans, viruses, malware, and adware from the infected computer. To fully protect the computer against TrojanSpy:MSIL/AgentTesla or similar attacks, you can activate Sophos to have real-time scanning and complete defense against all forms of threats.

1. Download Sophos Virus Removal Tool from the link below. Save the file on your computer where you can easily access it.

2. Once the download completes, browse the location of the file. Double-click to run the program and begin the install process.

3. On the first window of installation wizard, click Next to continue. Then, it will display the program’s License Agreement. You need to Accept the terms in order to proceed. If Windows prompts for User Account Control, please click Yes to proceed.

Screenshot of Sophos EULA Page

4. On succeeding windows, click Next or Continue to carry on with the installation. After completing the installation process, Launch Sophos Virus Removal Tool.

5. An internet connection is required when running this scanner in order to download important updates. Make sure that everything is up-to-date to effectively remove viruses like TrojanSpy:MSIL/AgentTesla.

6. Click the Start Scanning button to  carry out the Scan. This will check the system for the presence of malicious objects, malware, and viruses. The tool reveals items that were found linked to TrojanSpy:MSIL/AgentTesla and other suspicious entities. Be sure to remove all identified threats.

Screenshot of Sophos Virus Scan

After executing the above instructions, TrojanSpy:MSIL/AgentTesla should have been completely removed from the computer. If there are still signs of infection or the computer is displaying unusual behaviors, please continue with the remaining procedures.

Step 3 : Double Check with Windows Security Apps

Microsoft Windows has a built-in security application that you can use to double-check if your computer is still infected with TrojanSpy:MSIL/AgentTesla. For Windows 8 and 10/11 users, please run Windows Security. Users of Windows Vista and older versions can utilize Microsoft Security Essentials to remove the TrojanSpy:MSIL/AgentTesla virus.

Windows 8 / 10 / 11 Instructions:

Windows Security is a free tool that was built to help you remove TrojanSpy:MSIL/AgentTesla, viruses, and other malicious items from Windows 8 or Windows 10/11 systems. Follow these procedures to scan your computer with the tool:

1. Tap or click the Search charm, search for Windows Security, and then open the application.

Image of Windows Security Search

2. On the Home tab, click Virus and threat protection from the sidebar.

3. On the main window, click on Scan Options. Then, click on Full Scan button.

Image of Scan Options

4. Lastly, click on the Scan now button to start scanning for the presence of TrojanSpy:MSIL/AgentTesla. The process may take a while to complete.

5. After the scan, Delete/Quarantine identified threats, whether they were relevant to TrojanSpy:MSIL/AgentTesla or not. You may now restart Windows to complete the virus removal process.

How to protect the computer from TrojanSpy:MSIL/AgentTesla?

The initial defense that comes to mind for any computer user is to install an anti-virus or anti-malware program. This move is sensible and probably the most practical way to protect the computer against a TrojanSpy:MSIL/AgentTesla attack. Hence, keep in mind that having security software does not guarantee full protection. The majority of the prevention still lies in being cautious of users, and therefore, we are providing the following information as guidelines to protect the computer from virus infection.

Avoid Malicious Websites

There are enormous numbers of websites that were made for the primary purpose of spreading TrojanSpy:MSIL/AgentTesla. Normally, these sites are involved in integrating malicious pop-up and browser hijacker, that will eventually cause further virus infections. Avoid such websites.

Ignore and Delete Phishing Emails

The mass-mailing of computer viruses gives the attackers the luxury of spreading their malicious code in just one send-off. This will arrive in the inbox as an email that appears to be from a legitimate organization. So, if you receive an unexpected email with a link or an attached file, better delete it immediately.

Do Not Click a Suspicious Link

Links from social media, forums, and blog sites are sometimes being utilized by attackers to drive web users to a malicious page that contains malicious code. Therefore, do not just click on any link, especially if it looks suspicious. Accidental access to the destination site may lead to a TrojanSpy:MSIL/AgentTesla infection.

Be Careful When Downloading Files

Cracked software, serial key generators, and several freeware are seen as another method that spreads the TrojanSpy:MSIL/AgentTesla virus. Avoid acquiring these types of applications, and if there is a need to download freeware or shareware, be sure to obtain it from the official website or trusted providers.

About the author

2 thoughts on “TrojanSpy:MSIL/AgentTesla”

  1. Could i be getting false positives? While malware bytes does not scan it, and my windows defender does. I had the Phonzy Trojan and now a day later Tesla trojan.
    My malwarebytes didnt find the Tesla one. But my windows defender did.

  2. @K, if Windows Defender can detect it, you must use the same program to remove the threat. Also, make sure that both your MBAM and WD are up to date.

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