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Removal
Manual removal of a rootkit is often too difficult for a typical computer user,[24] but a number of security-software vendors offer tools to automatically detect and remove some rootkits, typically as part of an antivirus suite. As of 2005[update], Microsoft's monthly Windows Malicious Software Removal Tool is able to detect and remove some classes of rootkits.[72][73] Some antivirus scanners can bypass file system APIs, which are vulnerable to manipulation by a rootkit. Instead, they access raw filesystem structures directly, and use this information to validate the results from the system APIs to identify any differences that may be caused by a rootkit.[Notes 2][74][75][76][77]

***There are experts who believe that the only reliable way to remove them is to re-install the operating system from trusted media.[78][79] This is because antivirus and malware removal tools running on an untrusted system may be ineffective against well-written kernel-mode rootkits. Booting an alternate operating system from trusted media can allow an infected system volume to be mounted and potentially safely cleaned and critical data to be copied off—or, alternatively, a forensic examination performed.[23] Lightweight operating systems such as Windows PE, Windows Recovery Console, Windows Recovery Environment, BartPE, or Live Distros can be used for this purpose, allowing the system to be cleaned.
Even if the type and nature of a rootkit is known, manual repair may be impractical, while re-installing the operating system and applications is safer, simpler and quicker

Rootkit - Wikipedia, the free encyclopedia