hacktricks/linux-hardening/linux-privilege-escalation-checklist.md

Checklist - Linux Privilege Escalation

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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
• 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

• Check for useful software installed
• Check for vulnerable software installed

Processes

• Is any unknown software running?
• Is any software running with more privileges than it should have?
• Search for exploits of running processes (especially the version running).
• 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 or are 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 a 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 command 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 Location/Owned files, you may have access to 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?

Support HackTricks and get benefits!

• Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access to the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!

• Discover The PEASS Family, our collection of exclusive NFTs

• Get the official PEASS & HackTricks swag

• Join the 💬 Discord group or the telegram group or follow me on Twitter 🐦@carlospolopm.

• Share your hacking tricks by submitting PRs to the hacktricks github repo.