Enumeration

List Current Processes

RFS85@htb[/htb]$ ps aux | grep root

root         1  1.3  0.1  37656  5664 ?        Ss   23:26   0:01 /sbin/init
root         2  0.0  0.0      0     0 ?        S    23:26   0:00 [kthreadd]
root         3  0.0  0.0      0     0 ?        S    23:26   0:00 [ksoftirqd/0]
root         4  0.0  0.0      0     0 ?        S    23:26   0:00 [kworker/0:0]
root         5  0.0  0.0      0     0 ?        S<   23:26   0:00 [kworker/0:0H]
root         6  0.0  0.0      0     0 ?        S    23:26   0:00 [kworker/u8:0]
root         7  0.0  0.0      0     0 ?        S    23:26   0:00 [rcu_sched]
root         8  0.0  0.0      0     0 ?        S    23:26   0:00 [rcu_bh]
root         9  0.0  0.0      0     0 ?        S    23:26   0:00 [migration/0]

<SNIP>

List Current Processes

RFS85@htb[/htb]$ ps au

USER       		PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      		1256  0.0  0.1  65832  3364 tty1     Ss   23:26   0:00 /bin/login --
cliff.moore     1322  0.0  0.1  22600  5160 tty1     S    23:26   0:00 -bash
shared     		1367  0.0  0.1  22568  5116 pts/0    Ss   23:27   0:00 -bash
root      		1384  0.0  0.1  52700  3812 tty1     S    23:29   0:00 sudo su
root      		1385  0.0  0.1  52284  3448 tty1     S    23:29   0:00 su
root      		1386  0.0  0.1  21224  3764 tty1     S+   23:29   0:00 bash
shared     		1397  0.0  0.1  37364  3428 pts/0    R+   23:30   0:00 ps au

Home Directory Contents

RFS85@htb[/htb]$ ls /home

backupsvc  bob.jones  cliff.moore  logger  mrb3n  shared  stacey.jenkins

User's Home Directory Contents

RFS85@htb[/htb]$ ls -la /home/stacey.jenkins/

total 32
drwxr-xr-x 3 stacey.jenkins stacey.jenkins 4096 Aug 30 23:37 .
drwxr-xr-x 9 root           root           4096 Aug 30 23:33 ..
-rw------- 1 stacey.jenkins stacey.jenkins   41 Aug 30 23:35 .bash_history
-rw-r--r-- 1 stacey.jenkins stacey.jenkins  220 Sep  1  2015 .bash_logout
-rw-r--r-- 1 stacey.jenkins stacey.jenkins 3771 Sep  1  2015 .bashrc
-rw-r--r-- 1 stacey.jenkins stacey.jenkins   97 Aug 30 23:37 config.json
-rw-r--r-- 1 stacey.jenkins stacey.jenkins  655 May 16  2017 .profile
drwx------ 2 stacey.jenkins stacey.jenkins 4096 Aug 30 23:35 .ssh

SSH Directory Contents

RFS85@htb[/htb]$ ls -l ~/.ssh

total 8
-rw------- 1 mrb3n mrb3n 1679 Aug 30 23:37 id_rsa
-rw-r--r-- 1 mrb3n mrb3n  393 Aug 30 23:37 id_rsa.pub

Bash History

RFS85@htb[/htb]$ history

    1  id
    2  cd /home/cliff.moore
    3  exit
    4  touch backup.sh
    5  tail /var/log/apache2/error.log
    6  ssh [email protected]
    7  history

Sudo - List User's Privileges

RFS85@htb[/htb]$ sudo -l

Matching Defaults entries for sysadm on NIX02:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin

User sysadm may run the following commands on NIX02:
    (root) NOPASSWD: /usr/sbin/tcpdump

Configuration Files: Configuration files can hold a wealth of information. It is worth searching through all files that end in extensions such as .conf and .config, for usernames, passwords, and other secrets.

Readable Shadow File: If the shadow file is readable, you will be able to gather password hashes for all users who have a password set. While this does not guarantee further access, these hashes can be subjected to an offline brute-force attack to recover the cleartext password.

Password Hashes in /etc/passwd: Occasionally, you will see password hashes directly in the /etc/passwd file. This file is readable by all users, and as with hashes in the shadow file, these can be subjected to an offline password cracking attack. This configuration, while not common, can sometimes be seen on embedded devices and routers.

Passwd

RFS85@htb[/htb]$ cat /etc/passwd

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
<...SNIP...>
dnsmasq:x:109:65534:dnsmasq,,,:/var/lib/misc:/bin/false
sshd:x:110:65534::/var/run/sshd:/usr/sbin/nologin
mrb3n:x:1000:1000:mrb3n,,,:/home/mrb3n:/bin/bash
colord:x:111:118:colord colour management daemon,,,:/var/lib/colord:/bin/false
backupsvc:x:1001:1001::/home/backupsvc:
bob.jones:x:1002:1002::/home/bob.jones:
cliff.moore:x:1003:1003::/home/cliff.moore:
logger:x:1004:1004::/home/logger:
shared:x:1005:1005::/home/shared:
stacey.jenkins:x:1006:1006::/home/stacey.jenkins:
sysadm:$6$vdH7vuQIv6anIBWg$Ysk.UZzI7WxYUBYt8WRIWF0EzWlksOElDE0HLYinee38QI1A.0HW7WZCrUhZ9wwDz13bPpkTjNuRoUGYhwFE11:1007:1007::/home/sysadm:

Cron Jobs

RFS85@htb[/htb]$ ls -la /etc/cron.daily/

total 60
drwxr-xr-x  2 root root 4096 Aug 30 23:49 .
drwxr-xr-x 93 root root 4096 Aug 30 23:47 ..
-rwxr-xr-x  1 root root  376 Mar 31  2016 apport
-rwxr-xr-x  1 root root 1474 Sep 26  2017 apt-compat
-rwx--x--x  1 root root  379 Aug 30 23:49 backup
-rwxr-xr-x  1 root root  355 May 22  2012 bsdmainutils
-rwxr-xr-x  1 root root 1597 Nov 27  2015 dpkg
-rwxr-xr-x  1 root root  372 May  6  2015 logrotate
-rwxr-xr-x  1 root root 1293 Nov  6  2015 man-db
-rwxr-xr-x  1 root root  539 Jul 16  2014 mdadm
-rwxr-xr-x  1 root root  435 Nov 18  2014 mlocate
-rwxr-xr-x  1 root root  249 Nov 12  2015 passwd
-rw-r--r--  1 root root  102 Apr  5  2016 .placeholder
-rwxr-xr-x  1 root root 3449 Feb 26  2016 popularity-contest
-rwxr-xr-x  1 root root  214 May 24  2016 update-notifier-common

File Systems & Additional Drives

RFS85@htb[/htb]$ lsblk

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   30G  0 disk 
├─sda1   8:1    0   29G  0 part /
├─sda2   8:2    0    1K  0 part 
└─sda5   8:5    0  975M  0 part [SWAP]
sr0     11:0    1  848M  0 rom 

Find Writable Directories

RFS85@htb[/htb]$ find / -path /proc -prune -o -type d -perm -o+w 2>/dev/null

/dmz-backups
/tmp
/tmp/VMwareDnD
/tmp/.XIM-unix
/tmp/.Test-unix
/tmp/.X11-unix
/tmp/systemd-private-8a2c51fcbad240d09578916b47b0bb17-systemd-timesyncd.service-TIecv0/tmp
/tmp/.font-unix
/tmp/.ICE-unix
/proc
/dev/mqueue
/dev/shm
/var/tmp
/var/tmp/systemd-private-8a2c51fcbad240d09578916b47b0bb17-systemd-timesyncd.service-hm6Qdl/tmp
/var/crash
/run/lock

Find Writable Files

RFS85@htb[/htb]$ find / -path /proc -prune -o -type f -perm -o+w 2>/dev/null

/etc/cron.daily/backup
/dmz-backups/backup.sh
/proc
/sys/fs/cgroup/memory/init.scope/cgroup.event_control

<SNIP>

/home/backupsvc/backup.sh

<SNIP>

Last updated