What is TrojanSpy:MSIL/AgentTesla?

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 are also in danger once the system is infected with this virus. It is able to collect several data including username, password, IP address, ISP, Network setup, and computer configuration. If TrojanSpy:MSIL/AgentTesla is identified in the computer, it denotes that a more hazardous virus is about to infiltrate the system and therefore, user must perform an anti-virus scan immediately to avoid any further contamination.

Threat Behavior

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 update, 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 the operating system to run the malicious code during boot-up and it 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 one and thus, it can evade detection.


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

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


FileRepMalware (AVG), TR/Kryptik.qstjk (Avira), Trojan.GenericKD.34610370 (BitDefender), Trojan.PackedNET.276 (DrWeb), Trojan.GenericKD.34610370 (Emsisoft), A Variant Of MSIL/Kryptik.XXF (ESET-NOD32), HEUR:Trojan-DDoS.MSIL.MPDD.gen (Kaspersky), Backdoor.RevengeRAT (Malwarebytes), GenericRXJT-UO!3C5195E38DF6 (McAfee), Mal/Generic-S (Sophos), TROJ_GEN.R002C0DIS20 (TrendMicro), Trojan.Win32.Generic!BT (VIPRE), W32.Trojan.Gen (Webroot)

List of Variants

Versions of TrojanSpy:MSIL/AgentTesla
Version Name Alert Level Date Added
TrojanSpy:MSIL/AgentTesla.gen!bit Severe Jun 11, 2018
TrojanSpy:MSIL/AgentTesla!MTB Severe Nov 14, 2019
TrojanSpy:MSIL/AgentTesla!MSR Severe Apr 15, 2020
TrojanSpy:MSIL/AgentTesla.AO!MTB Severe Apr 22, 2020
TrojanSpy:MSIL/AgentTesla.AP!rfn Severe May 16, 2020
TrojanSpy:MSIL/AgentTesla.SS!MTB Severe May 20, 2020
TrojanSpy:MSIL/AgentTesla.YG!MTB Severe Jul 07, 2020
TrojanSpy:MSIL/AgentTesla.PK!MTB Severe Nov 23, 2020
TrojanSpy:MSIL/AgentTesla.SP!rfn Severe Nov 24, 2020
For complete details including full list of TrojanSpy:MSIL/AgentTesla variants, please refer to this Microsoft Security Intelligence page

How to remove TrojanSpy:MSIL/AgentTesla?

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

Remove TrojanSpy:MSIL/AgentTesla Instantly

To instantly remove TrojanSpy:MSIL/AgentTesla, we suggest that you scan the infected computer with this powerful anti-malware 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 attack, you can activate Malwarebytes to have real-time scanning and complete defense against all forms of threats.

1. Download Malwarebytes Anti-Malware from the link below. Save the file on your hard drive.

2. Once the download completes, double-click on the file MBSetup.exe to run the program.

3. Select desired installation package whether for Personal Computer or Work Computer.

4. On next window, click Install button to proceed.

5. Just proceed with the succeeding prompts until it start to execute the installation procedure.

6. Installation process will take less than a minute. It should run automatically after completing the setup.

7. When Malwarebytes Anti-Malware interface appears, please select Scan on the menu. The program will check for any available update before proceeding. Do not skip this step. Virus scan may take a while, please wait for the process to finish.

8. When scanning is done, Malwarebytes Anti-Malware will display the list of identified threats. Remove all and restart the computer to finalized the scan process.

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

Stage 1 : Start Windows in Safe Mode With Networking

Windows 10 Guide

1. Click on Windows logo and select Power icon when options pop-ups.
2. Select Restart from the options while pressing Shift key on the keyboard.
3. Choose an Option window will appear, select the Troubleshoot button.
4. On next window, please choose Advanced Option.
5. On Advanced Option window, click on Startup Settings and then, click Restart button to reboot the computer.
6. When Windows boot on Startup Settings, press function key F5 or number 5 on 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 Windows Start icon at the lower left section of the screen.
2. Open Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup and then, click on Restart Now button.
4. Once the computer starts in Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings and then, click Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.

Stage 2 :Double Check with Microsoft Security Apps

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

Windows 8 / 10 Instructions:

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

1. Tap or click the Search charm, search for defender, and then open Windows Defender.

If Windows Defender is not yet installed on the computer, please proceed to download page using the link below. It also contains detailed instruction to install and use the program effectively. Proper usage is required to totally remove TrojanSpy:MSIL/AgentTesla

2. On the Home tab, click Full under Scan Options. Click Scan now to start scanning for presence of TrojanSpy:MSIL/AgentTesla. The process may take a while to complete.

3. After the scan, delete/quarantine identified threats wether it is relevant to TrojanSpy:MSIL/AgentTesla or not. You may now restart Windows to complete the virus removal process.

Windows XP, Windows Vista, and Windows 7 Instructions:

1. Open Microsoft Security Essentials by going to Windows Start > All Programs. If the tool is not yet installed on the computer, please download Microsoft Security Essentials from the link below. Save the file on your hard drive.

Complete installation guide and usage are also provided on the same link. It is essential in removing TrojanSpy:MSIL/AgentTesla effectively. If Microsoft Security Essentials is already installed on the PC, please proceed with the steps below.

2. On Microsoft Security Essentials Home screen, please choose Full under Scan Options.

3. Click on Scan Now button to start detecting TrojanSpy:MSIL/AgentTesla items, viruses, and malware on the PC. Scan may take a while, please be patient and wait for the process to end.

How to protect the computer?

The initial defense that comes to the mind of any computer users 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 TrojanSpy:MSIL/AgentTesla attack. Hence, keep in mind that having a security software do not give full guarantee of protection. The most part of the prevention still lies on 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 was 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 infection. Avoid such kind of websites.

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 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 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 application and if there is a need to download a freeware or shareware, be sure to obtain it from the official website or trusted providers.

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