privilege-escalation-linux
PRIVILEGE-ESCALATION-LINUX RSS Search BlogArchivesScriptsVideos Basic Linux Privilege Escalation Before starting, I would like to point out - I'm no expert. As far as I know, there isn't a "magic" answer, in this huge area. This is simply my finding, typed up, to be shared (my starting point). Below is a mixture of commands to do the same thing, to look at things in a different place or just a different light. I know there more "things" to look for. It's just a basic & rough guide. Not every command will work for each system as Linux varies so much. "It" will not jump off the screen - you've to hunt for that "little thing" as "the devil is in the detail".
Enumeration is the key.
(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. Operating System
What's the distribution type? What version?
cat /etc/issue cat /etc/*-release cat /etc/lsb-release # Debian based cat /etc/redhat-release # Redhat based What's the kernel version? Is it 64-bit?
cat /proc/version uname -a uname -mrs rpm -q kernel dmesg | grep Linux ls /boot | grep vmlinuz- What can be learnt from the environmental variables?
cat /etc/profile cat /etc/bashrc cat ~/.bash_profile cat ~/.bashrc cat ~/.bash_logout env set Is there a printer?
lpstat -a Applications & Services
What services are running? Which service has which user privilege?
ps aux ps -ef top cat /etc/services Which service(s) are been running by root? Of these services, which are vulnerable - it's worth a double check!
ps aux | grep root ps -ef | grep root What applications are installed? What version are they? Are they currently running?
ls -alh /usr/bin/ ls -alh /sbin/ dpkg -l rpm -qa ls -alh /var/cache/apt/archivesO ls -alh /var/cache/yum/ Any of the service(s) settings misconfigured? Are any (vulnerable) plugins attached?
cat /etc/syslog.conf cat /etc/chttp.conf cat /etc/lighttpd.conf cat /etc/cups/cupsd.conf cat /etc/inetd.conf cat /etc/apache2/apache2.conf cat /etc/my.conf cat /etc/httpd/conf/httpd.conf cat /opt/lampp/etc/httpd.conf ls -aRl /etc/ | awk '$1 ~ /^.r./ What jobs are scheduled?
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 Any plain text usernames and/or 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 Communications & Networking
What NIC(s) does the system have? Is it connected to another network?
/sbin/ifconfig -a cat /etc/network/interfaces cat /etc/sysconfig/network What are the network configuration settings? What can you find out about this network? DHCP server? DNS server? Gateway?
cat /etc/resolv.conf cat /etc/sysconfig/network cat /etc/networks iptables -L hostname dnsdomainname What other users & hosts are communicating with the system?
lsof -i lsof -i :80 grep 80 /etc/services netstat -antup netstat -antpx netstat -tulpn chkconfig --list chkconfig --list | grep 3:on last w Whats cached? IP and/or MAC addresses
arp -e route /sbin/route -nee Is packet sniffing possible? What can be seen? Listen to live traffic
1 tcpdump tcp dst 192.168.1.7 80 and tcp dst 10.5.5.252 21 Note: tcpdump tcp dst [ip] [port] and tcp dst [ip] [port]
Have you got a shell? Can you interact with the system?
Is port forwarding possible? Redirect and interact with traffic from another view
Note: FPipe.exe -l [local port] -r [remote port] -s [local port] [local IP]
FPipe.exe -l 80 -r 80 -s 80 192.168.1.7 Note: ssh -[L/R] [local port]:[remote ip]:[remote port] [local user]@[local ip]
ssh -L 8080:127.0.0.1:80 root@192.168.1.7 # Local Port ssh -R 8080:127.0.0.1:80 root@192.168.1.7 # Remote Port Note: mknod backpipe p ; nc -l -p [remote port] < backpipe | nc [local IP] [local port] >backpipe
mknod backpipe p ; nc -l -p 8080 < backpipe | nc 10.5.5.151 80 >backpipe # Port Relay mknod backpipe p ; nc -l -p 8080 0 & < backpipe | tee -a inflow | nc localhost 80 | tee -a outflow 1>backpipe # Proxy (Port 80 to 8080) mknod backpipe p ; nc -l -p 8080 0 & < backpipe | tee -a inflow | nc localhost 80 | tee -a outflow & 1>backpipe # Proxy monitor (Port 80 to 8080) Is tunnelling possible? Send commands locally, remotely
ssh -D 127.0.0.1:9050 -N [username]@[ip] proxychains ifconfig Confidential Information & Users
Who are you? Who is logged in? Who has been logged in? Who else is there? Who can do what?
id who w last cat /etc/passwd | cut -d: -f1 # List of 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 cat /etc/sudoers sudo -l What sensitive files can be found?
cat /etc/passwd cat /etc/group cat /etc/shadow ls -alh /var/mail/ Anything "interesting" in the home directorie(s)? If it's possible to access
ls -ahlR /root/ ls -ahlR /home/ Are there any passwords in; scripts, databases, configuration files or log files? Default paths and locations for passwords
cat /var/apache2/config.inc cat /var/lib/mysql/mysql/user.MYD cat /root/anaconda-ks.cfg What has the user being doing? Is there any password in plain text? What have they been edting?
cat ~/.bash_history cat ~/.nano_history cat ~/.atftp_history cat ~/.mysql_history cat ~/.php_history What user information can be found?
cat ~/.bashrc cat ~/.profile cat /var/mail/root cat /var/spool/mail/root Can private-key information be found?
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 File Systems
Which configuration files can be written in /etc/? Able to reconfigure a service?
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 What can be found in /var/ ?
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 settings/files (hidden) on website? Any settings file with database information?
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/ Is there anything in the log file(s) (Could help with "Local File Includes"!)
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/
If commands are limited, you break out of the "jail" shell?
python -c 'import pty;pty.spawn("/bin/bash")' echo os.system('/bin/bash') /bin/sh -i How are file-systems mounted?
mount df -h Are there any unmounted file-systems?
1 cat /etc/fstab What "Advanced Linux File Permissions" are used? 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 Where can written to and executed from? A few 'common' places: /tmp, /var/tmp, /dev/shm
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 Any "problem" files? Word-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 Preparation & Finding Exploit Code
What development tools/languages are installed/supported?
find / -name perl find / -name python find / -name gcc* find / -name cc How can files be uploaded?
1 2 3 4 5 find / -name wget find / -name nc find / -name netcat find / -name tftp* find / -name ftp Finding exploit code
Finding more information regarding the exploit
(Quick) "Common" exploits. Warning. Pre-compiled binaries files. Use at your own risk
Mitigations
Is any of the above information easy to find?
Try doing it! Setup a cron job which automates script(s) and/or 3rd party products
Is the system fully patched?
Kernel, operating system, all applications, their plugins and web services
1 2 apt-get update && apt-get upgrade yum update Are services running with the minimum level of privileges required?
For example, do you need to run MySQL as root?
Scripts Can any of this be automated?!
Other (quick) guides & Links
Enumeration
Misc
Posted by g0tmi1kAug 2nd, 2011 12:00 am bypassing, commands, privilege escalation
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