smb

On looking for SMb shares I found one share having read permission on null session and is named as backups.

I will connect to this backups share and see it's content

smbclient   //192.168.231.71/backups -U "%"

┌──(kali㉿kali)-[~/pg/bratarina]
└─$ smbclient   //192.168.231.71/backups -U "%"
Try "help" to get a list of possible commands.
smb: \> ld
ld: command not found
smb: \> ls
  .                                   D        0  Mon Jul  6 13:16:41 2020
  ..                                  D        0  Mon Jul  6 13:16:41 2020
  passwd.bak                          N     1747  Mon Jul  6 13:16:41 2020

                10253588 blocks of size 1024. 6300724 blocks available
smb: \> get passwd.bak
getting file \passwd.bak of size 1747 as passwd.bak (5.5 KiloBytes/sec) (average 5.5 KiloBytes/sec)

Looking at the passwd.bak revealed that It is a backup file of /etc/passwd file.

┌──(kali㉿kali)-[~/pg/bratarina]
└─$ cat passwd.bak
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
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-network:x:100:102:systemd Network Management,,,:/run/systemd/netif:/usr/sbin/nologin
systemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd/resolve:/usr/sbin/nologin
syslog:x:102:106::/home/syslog:/usr/sbin/nologin
messagebus:x:103:107::/nonexistent:/usr/sbin/nologin
_apt:x:104:65534::/nonexistent:/usr/sbin/nologin
lxd:x:105:65534::/var/lib/lxd/:/bin/false
uuidd:x:106:110::/run/uuidd:/usr/sbin/nologin
dnsmasq:x:107:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
landscape:x:108:112::/var/lib/landscape:/usr/sbin/nologin
sshd:x:109:65534::/run/sshd:/usr/sbin/nologin
pollinate:x:110:1::/var/cache/pollinate:/bin/false
neil:x:1000:1000:neil,,,:/home/neil:/bin/bash
_smtpd:x:1001:1001:SMTP Daemon:/var/empty:/sbin/nologin
_smtpq:x:1002:1002:SMTPD Queue:/var/empty:/sbin/nologin
postgres:x:111:116:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash

From the content we came to know about user and its username associated with it. neil is a user who has shell access.