A friend once installed a remote-access trojan on my laptop as a joke. It reportedly ran in the background and connected to a webhook, allowing them to view or interact with the computer through commands. I was told it was written in C# and Python.
I reset the laptop soon afterward and have repeated the process many times since then. I've tried USB-based clean installations, local and cloud reinstalls, and the option that removes everything as if the laptop were being prepared for a new owner. Windows scans have not found anything, but I'm unsure whether they would detect a simple C# or Python-based RAT.
I'm worried the malware could survive a reset or that my friend might still have access to my email, banking, or other sensitive accounts. We no longer communicate. If Windows has been completely wiped and reinstalled from USB or the cloud, how can I verify that the RAT is gone? Could something like this survive a clean reinstall, and what other checks should I perform? I realize I may be overthinking this, but I'd like to establish a reasonable way to confirm the laptop is safe instead of repeatedly resetting it.
4 Answers
There is no ordinary scan that can mathematically prove a negative, but you can use sensible checks: install current firmware and Windows updates, run a full security scan, inspect startup applications and scheduled tasks, and look for unexpected network connections after the clean install. If all of that is normal, repeatedly reinstalling Windows is unlikely to provide additional safety and may be feeding the anxiety rather than uncovering anything new.
A proper clean installation is generally enough for a basic RAT like the one you described. Boot from trusted Windows installation media, delete the existing partitions during setup, and install Windows into the unallocated space. That removes the old operating system and files. Afterward, fully update Windows, enable its security features, and install applications only from reputable sources.
In theory, highly sophisticated malware such as a firmware implant or bootkit could survive an operating-system reinstall. In practice, a casually written C# or Python RAT is extremely unlikely to have that capability. If the laptop is clean after a partition wipe and reinstall, there are no suspicious processes or network connections, and your accounts show no unusual activity, you have strong practical evidence that it’s gone.
Also secure the accounts rather than focusing only on the laptop. From a different trusted device, change your email and financial-account passwords, use unique passwords, enable two-factor authentication, review active sessions and recovery options, and revoke unfamiliar application access. Check bank and email activity as well. Those steps protect you even if credentials were exposed before the reinstall.
So a normal RAT would not usually have access to the BIOS or firmware just because it was running in Windows?