Anatomy of Kernel-Level Rootkits and Digital Forensics Triage

#Invasive Kernel Space Hooking Vectors#link

Unlike user-space trojans that manipulate file properties or spawn rogue processes, kernel-space rootkits manipulate Ring 0. By intercepting core system operations, a rootkit can render processes, files, and incoming network packets completely invisible to standard operators.

Intercepting System Call Handlers

The snippet below represents a mock kernel driver loading sequence that modifies the `sys_call_table` array index to redirect standard directory inquiries from their legitimate handler to a custom compromised routine.

/* Sycall Pointer Hijacking Code Snippet */
unsigned long *sys_call_table;
asmlinkage int (*original_sys_getdents)(unsigned int, struct linux_dirent *, unsigned int);

asmlinkage int hooked_sys_getdents(unsigned int fd, struct linux_dirent *dirp, unsigned int count) {
    // Intercept read buffers, locate target process prefix, and filter from list
    int ret = original_sys_getdents(fd, dirp, count);
    filter_malicious_nodes(dirp, &ret);
    return ret;
}

Conducting Volatility Forensics Auditing

To detect pointer redirections, incident response technicians acquire a RAM memory dump and run specialized volatility plugins to audit original system vectors. Run the terminal below to simulate kernel system call validations.

Memory Ring Access Architecture

Understanding protection boundaries of CPU instruction execution is vital for triage. Below is a breakdown of memory architecture access classes.

Ring Architecture Knowledge Check

Answer the question below to confirm your understanding of operating system ring protection boundaries.