Useful for both pentesters and systems administrators, this checklist is focused on privilege escalation on GNU/Linux operating systems. Many of these will also apply to Unix systems, (FreeBSD, Solaris, etc.) and some may apply to Windows. The following information is based on the assumption that you have CLI access to the system as non-root user.
This list is far from complete, it will be periodically updated.
- Are there any hashes in /etc/passwd? If so, can they be cracked quickly? (JtR, HashCat)
- Is /etc/shadow readable? If so, are the hashes easily crackable?
- Is /etc/passwd or /etc/shadow writeable?
- Any passwords in configuration or other files? Is the root password one of those?
- Does the current user have sudo rights at all? If so, how can they be abused?
- Check /home, /root, /etc/ssh for readable private ssh keys.
- Check /home, /root, /etc/ssh for writeable public ssh keys. (authorized_keys) . If not, can an authorized_keys file be created for another user?
- Kernel exploits?
- Check for SUID/SGID files that may give you read/write/execute access to sensitive files.
- Vulnerable/exploitable SUID/SGID executables.
- Vulnerable/exploitable files with special capabilities. (This is detailed here)
- Vulnerable/exploitable services running as another user/root, or that allow shell commands or other system access? (VNC as root for example)
- Is /root/.bashrc or /home/*/.bashrc writeable? If so, malicious commands can be added to that file, will run when the user/root logs in.
- Writeable cron jobs, or other executables/scripts that are run by root.
- Replaceable/writeable modules/libraries that are used by privileged executables/scripts/processes.
- Writeable configuration files (*.conf) that are used by privileges executables/scripts/processes.
- Are there any interesting files in /var/mail/ or /home/*/? Any passwords or useful info in /home/*/.bash_history?