Trojan:MSIL/AMSIBypass.KK!MTB

Question

I have this malware appearing on my computer and would like to understand the best steps to remove it.

Answer 1

Trojan:MSIL/AMSIBypass.KK!MTB is detected as a trojan, a type of malware that must be introduced to the device (for example by downloading or running a malicious file) and does not spread by itself.

To remove it and check for other malware, follow these steps using Microsoft security tools:

1. Run Microsoft Defender Antivirus
   • Ensure Microsoft Defender Antivirus is enabled and up to date on Windows 10/11.
   • Run a full scan of the device. Trojans commonly download and install additional malware, so a full scan is important.
2. Run Microsoft Safety Scanner
   • Download and run the latest version of Microsoft Safety Scanner.
   • Perform a full scan. This can take some time because all fixed and removable drives are scanned.
3. Run Windows Malicious Software Removal Tool (MSRT)
   • Make sure Windows Update is enabled so that the latest MSRT is delivered with updates.
   • When MSRT detects malicious software, it may prompt for a full scan. Allow the full scan to run; it scans all fixed and removable drives (not mapped network drives).
   • If malicious files are found, follow the prompts to remove or clean them. Be aware that some data loss is possible if infected files cannot be fully restored.
   • If prompted, restart the computer to complete removal.
4. Check for symptoms and fake alerts
   • If the device shows symptoms such as unusual slowness, frequent crashes, inability to open security-related sites, unexpected browser home page changes, or constant pop‑ups, continue using the tools above until scans are clean.
   • Be cautious of fake virus alerts or scareware that claim infection and try to lure into fraudulent actions. Use only Microsoft’s built‑in tools and trusted Microsoft pages for guidance.
5. After cleanup
   • Keep Windows Update turned on so security updates and new versions of MSRT are installed automatically.
   • Keep Microsoft Defender Antivirus real‑time protection enabled.
   • Avoid downloading software from untrusted or mirror sites, and be careful with email attachments and links, as trojans often masquerade as legitimate applications.

If problems persist or tools continue to detect malware, use Microsoft’s malware support options for additional assistance.

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References:

• Trojans
• Remove specific prevalent malware with Windows Malicious Software Removal Tool (KB890830)
• Microsoft resources and guidance for removal of malware and viruses