A rootkit is a type of malicious software designed to provide an attacker with unauthorized access to a computer system while concealing its presence. Rootkits achieve this by modifying the host’s operating system or other software to hide their existence, allowing the attacker to maintain control over the system without detection.

Definition and Purpose:

Rootkits are primarily used to gain and maintain root access (administrative privileges) on a system.

They disguise themselves as legitimate software or integrate deeply into the operating system to avoid detection.

Mechanisms of Action:

Kernel Mode Rootkits: These operate at the kernel level, which is the core of the operating system, making them very powerful and hard to detect.

User Mode Rootkits: These run in the same space as user applications, intercepting and altering standard system API calls to hide their presence.

Bootkits: These infect the Master Boot Record (MBR) or Volume Boot Record (VBR) and load before the operating system, making them extremely difficult to detect and remove.

Detection and Prevention:

Detection Tools: Tools like RootkitRevealer, Chkrootkit, and rkhunter can help in identifying rootkits.

Prevention: Regular system updates, use of strong antivirus and anti-malware solutions, and integrity checking tools like Tripwire can help in preventing rootkit infections.

Real-World Examples:

Sony BMG Rootkit: In 2005, Sony BMG included a rootkit in their digital rights management (DRM) software on music CDs. The rootkit hid files and processes, leading to a major scandal when it was discovered.

Stuxnet: This sophisticated worm included a rootkit component to hide its presence on infected systems, making it one of the most infamous examples of rootkit use in a cyber attack.

References from Pentesting Literature:

In "Penetration Testing - A Hands-on Introduction to Hacking" by Georgia Weidman, rootkits are discussed in the context of post-exploitation, where maintaining access to the compromised system is crucial.

Various HTB write-ups, such as the analysis of complex attacks involving multiple stages of exploitation, often highlight the use of rootkits in maintaining persistent access.

Step-by-Step ExplanationReferences:

Penetration Testing - A Hands-on Introduction to Hacking

HTB Official Writeups on sophisticated attacks

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