Checklist - Linux Privilege Escalation

Best tool to look for Linux local privilege escalation vectors: LinPEAS​

​System Information​

• Get OS information

• Check the PATH, any writable folder?

• Check env variables, any sensitive detail?

• Search for kernel exploits using scripts (DirtyCow?)

• Check if the sudo version is vulnerable​

• ​Dmesg signature verification failed error?

• More system enum (date, system stats, cpu info, printers)

• ​Enumerate more defenses​

​Drives​

• List mounted drives

• Any unmounted drive?

• Any creds in fstab?

​Installed Software​

1. Check for useful software installed

2. Check for vulnerable software installed

​Processes​

• Is any unknown software running?

• Is any software with more privileges that it should have running?

• Search for exploits for running processes (specially if running of versions)

• Can you modify the binary of any running process?

• Monitor processes and check if any interesting process is running frequently

• Can you read some interesting process memory (where passwords could be saved)?

​Scheduled/Cron jobs?​

• Is the PATH being modified by some cron and you can write in it?

• Any wildcard in a cron job?

• Some modifiable script is being executed or is inside modifiable folder?

• Have you detected that some script could be being executed very frequently? (every 1, 2 or 5 minutes)

​Services​

• Any writable .service file?

• Any writable binary executed by a service?

• Any writable folder in systemd PATH?

​Timers​

• Any writable timer?

​Sockets​

• Any writable .socket file?

• Can you communicate with any socket?

• HTTP sockets with interesting info?

​D-Bus​

• Can you communicate with any D-Bus?

​Network​

• Enumerate the network to know where you are

• Open ports you couldn't access before getting a shell inside the machine?

• Can you sniff traffic using tcpdump?

​Users​

• Generic users/groups enumeration

• Do you have a very big UID? Is the machine vulnerable?

• Can you escalate privileges thanks to a group you belong to?

• Clipboard data?

• Password Policy?

• Try to use every known password that you have discovered previously to login with each possible user. Try to login also without password.

​Writable PATH​

• If you have write privileges over some folder in PATH you may be able to escalate privileges

​SUDO and SUID commands​

• Can you execute any comand with sudo? Can you use it to READ, WRITE or EXECUTE anything as root? (GTFOBins)

• Is any exploitable suid binary? (GTFOBins)

• Are sudo commands limited by path? can you bypass the restrictions?

• ​Sudo/SUID binary without path indicated?

• ​SUID binary specifying path? Bypass

• ​LD_PRELOAD vuln​

• ​Lack of .so library in SUID binary from a writable folder?

• ​SUDO tokens available? Can you create a SUDO token?

• Can you read or modify sudoers files?

• Can you modify /etc/ld.so.conf.d/?

• ​OpenBSD DOAS command

​Capabilities​

• Has any binary any unexpected capability?

​ACLs​

• Has any file any unexpected ACL?

​Open Shell sessions​

• screen?

• tmux?

​SSH​

• Debian OpenSSL Predictable PRNG - CVE-2008-0166​

• ​SSH Interesting configuration values​

​Interesting Files​

• Profile files - Read sensitive data? Write to privesc?

• passwd/shadow files - Read sensitive data? Write to privesc?

• Check commonly interesting folders for sensitive data

• Weird Localtion/Owned files, you may have access or alter executable files

• Modified in last mins

• Sqlite DB files

• Hidden files

• Script/Binaries in PATH

• Web files (passwords?)

• Backups?

• Known files that contains passwords: Use Linpeas and LaZagne

• Generic search

​Writable Files​

• Modify python library to execute arbitrary commands?

• Can you modify log files? Logtotten exploit

• Can you modify /etc/sysconfig/network-scripts/? Centos/Redhat exploit

• Can you write in ini, int.d, systemd or rc.d files?

​Other tricks​

• Can you abuse NFS to escalate privileges?

• Do you need to escape from a restrictive shell?

If you want to know about my latest modifications/additions or you have any suggestion for HackTricks or PEASS, join the 💬 PEASS & HackTricks telegram group here, or follow me on Twitter 🐦​@carlospolopm. If you want to share some tricks with the community you can also submit pull requests to https://github.com/carlospolop/hacktricks that will be reflected in this book. Don't forget to give ⭐ on the github to motivate me to continue developing this book.

​Buy me a coffee here​