Exploiting Vulnserver with TRUN parameter

EASY STEPS

Part 1

  1. Fuzzing the service parameter and getting the crash byte
  2. Generating the pattern
  3. Finding the correct offset where the byte crashes with the help of (EIP)

Part 2

  1. Finding the bad character with mona.py, and comparing bad character strings with mona.py
  2. Finding…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.7 (protocol 2.0)
| ssh-hostkey:
| 2048 95:68:04:c7:42:03:04:cd:00:4e:36:7e:cd:4f:66:ea (RSA)
| 256 c3:06:5f:7f:17:b6:cb:bc:79:6b:46:46:cc:11:3a:7d (ECDSA)
|_ 256 63:0c:28:88:25:d5:48:19:82:bb:bd:72:c6:6c:68:50 (ED25519)
666/tcp open http Node.js Express framework
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-title: Site doesn’t have a title (text/html; charset=utf-8).
MAC Address: 08:00:27:D2:6A:4F (Oracle VirtualBox virtual NIC)
Device type: general…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 1024 10:cd:9e:a0:e4:e0:30:24:3e:bd:67:5f:75:4a:33:bf (DSA)
| 2048 bc:f9:24:07:2f:cb:76:80:0d:27:a6:48:52:0a:24:3a (RSA)
|_ 256 4d:bb:4a:c1:18:e8:da:d1:82:6f:58:52:9c:ee:34:5f (ECDSA)
25/tcp open smtp Postfix smtpd
|_smtp-commands: vulnix, PIPELINING, SIZE 10240000, VRFY, ETRN, STARTTLS, ENHANCEDSTATUSCODES, 8BITMIME, DSN,
|_ssl-date: 2019–10–16T11:55:10+00:00; -3s from scanner time.
79/tcp open finger Linux fingerd
|_finger…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.4p1 Debian 10+deb9u1 (protocol 2.0)
| ssh-hostkey:
| 2048 77:00:84:f5:78:b9:c7:d3:54:cf:71:2e:0d:52:6d:8b (RSA)
| 256 78:b8:3a:f6:60:19:06:91:f5:53:92:1d:3f:48:ed:53 (ECDSA)
|_ 256 e4:45:e9:ed:07:4d:73:69:43:5a:12:70:9d:c4:af:76 (ED25519)
25/tcp open smtp JAMES smtpd 2.3.2
|_smtp-commands: solidstate Hello nmap.scanme.org (10.0.0.1 [10.0.0.1]),
80/tcp open http Apache httpd 2.4.25 ((Debian))
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.4.25…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 1024 3c:3d:e3:8e:35:f9:da:74:20:ef:aa:49:4a:1d:ed:dd (DSA)
| 2048 85:94:6c:87:c9:a8:35:0f:2c:db:bb:c1:3f:2a:50:c1 (RSA)
| 256 f3:cd:aa:1d:05:f2:1e:8c:61:87:25:b6:f4:34:45:37 (ECDSA)
|_ 256 34:ec:16:dd:a7:cf:2a:86:45:ec:65:ea:05:43:89:21 (ED25519)
MAC Address: 08:00:27:D9:1F:A2 (Oracle VirtualBox virtual NIC)
Warning: OSScan results may be unreliable because we could not find at least 1 open and…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 1024 68:60:de:c2:2b:c6:16:d8:5b:88:be:e3:cc:a1:25:75 (DSA)
| 2048 50:db:75:ba:11:2f:43:c9:ab:14:40:6d:7f:a1:ee:e3 (RSA)
|_ 256 11:5d:55:29:8a:77:d8:08:b4:00:9b:a3:61:93:fe:e5 (ECDSA)
80/tcp open http Apache httpd 2.2.22 ((Ubuntu))
| http-methods:
|_ Supported Methods: OPTIONS GET HEAD POST
|_http-server-header: Apache/2.2.22 (Ubuntu)
|_http-title: Zico’s Shop
111/tcp open rpcbind 2–4 (RPC #100000)
| rpcinfo…

Nmap

PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.6p1 Ubuntu 4 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 7a:9b:b9:32:6f:95:77:10:c0:a0:80:35:34:b1:c0:00 (RSA)
| 256 24:0c:7a:82:78:18:2d:66:46:3b:1a:36:22:06:e1:a1 (ECDSA)
|_ 256 b9:15:59:78:85:78:9e:a5:e6:16:f6:cf:96:2d:1d:36 (ED25519)
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
| 100000 3,4 111/tcp6 rpcbind
| 100000…

Nmap

PORT STATE SERVICE VERSION
80/tcp open http Apache httpd 2.4.10 ((Debian))
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.4.10 (Debian)
|_http-title: PwnLab Intranet Image Hosting
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
| 100000 3,4 111/tcp6 rpcbind
| 100000 3,4…

Nmap

PORT STATE SERVICE VERSION
22/tcp closed ssh
80/tcp open http Apache httpd
|_http-favicon: Unknown favicon MD5: D41D8CD98F00B204E9800998ECF8427E
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache
|_http-title: Site doesn’t have a title (text/html).
443/tcp open ssl/http Apache httpd
|_http-favicon: Unknown favicon MD5: D41D8CD98F00B204E9800998ECF8427E
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache
|_http-title: Site doesn’t have…

Nmap

PORT STATE SERVICE VERSION
22/tcp filtered ssh
80/tcp open http Apache httpd 2.2.22 ((Debian))
| http-methods:
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.2.22 (Debian)
|_http-title: Site doesn’t have a title (text/html).
3128/tcp open http-proxy Squid http proxy 3.1.20
|_http-server-header: squid/3.1.20
|_http-title: ERROR: The requested URL could not be retrieved
MAC Address: 08:00:27:54:4A:37 (Oracle VirtualBox virtual NIC)
Device…

Raj Singh Chauhan

Security Researcher, Penetration Tester

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store