7.2 KiB
Kiosk Escape and Jail Breakout
Summary
- Methodology
- Gaining a command shell
- Sticky Keys
- Dialog Boxes
- Internet Explorer
- Shell URI Handlers
- References
Tools
- kiosk.vsim.xyz - tooling for browser-based, Kiosk mode testing.
Methodology
- Display global variables and their permissions:
export -p
- Switch to another user using
sudo
/su
- Basic privilege escalations such as CVE, sudo misconfiguration, etc. Comprehensive list at Linux / Windows
- List default commands in the restricted shell:
compgen -c
- Container escape if it's running inside a
Docker
/LXC
container - Pivot onto the network
- Scan other machines on the network or attempt SSRF exploitation
- Metadata for Cloud assets, see
cloud/aws
andcloud/azure
- Use globbing capability built inside the shell:
echo *
,echo .*
,echo /*
Gaining a command shell
- Shortcut
- [Window] + [R] -> cmd
- [CTRL] + [SHIFT] + [ESC] -> Task Manager
- [CTRL] + [ALT] + [DELETE] -> Task Manager
- Access through file browser: Browsing to the folder containing the binary (i.e.
C:\windows\system32\
), we can simply right click andopen
it - Drag-and-drop: dragging and dropping any file onto the cmd.exe
- Hyperlink:
file:///c:/Windows/System32/cmd.exe
- Task Manager:
File
>New Task (Run...)
>cmd
- MSPAINT.exe
- Open MSPaint.exe and set the canvas size to:
Width=6
andHeight=1
pixels - Zoom in to make the following tasks easier
- Using the colour picker, set pixels values to (from left to right):
1st: R: 10, G: 0, B: 0 2nd: R: 13, G: 10, B: 13 3rd: R: 100, G: 109, B: 99 4th: R: 120, G: 101, B: 46 5th: R: 0, G: 0, B: 101 6th: R: 0, G: 0, B: 0
- Save it as 24-bit Bitmap (.bmp;.dib)
- Change its extension from bmp to bat and run
- Open MSPaint.exe and set the canvas size to:
Sticky Keys
- Spawn the sticky keys dialog
- Via Shell URI :
shell:::{20D04FE0-3AEA-1069-A2D8-08002B30309D}
- Hit 5 times [SHIFT]
- Via Shell URI :
- Visit "Ease of Access Center"
- You land on "Setup Sticky Keys", move up a level on "Ease of Access Center"
- Start the OSK (On-Screen-Keyboard)
- You can now use the keyboard shortcut (CTRL+N)
Dialog Boxes
Creating new files
- Batch files – Right click > New > Text File > rename to .BAT (or .CMD) > edit > open
- Shortcuts – Right click > New > Shortcut >
%WINDIR%\system32
Open a new Windows Explorer instance
- Right click any folder > select
Open in new window
Exploring Context Menus
- Right click any file/folder and explore context menus
- Clicking
Properties
, especially on shortcuts, can yield further access viaOpen File Location
Save as
- "Save as" / "Open as" option
- "Print" feature – selecting "print to file" option (XPS/PDF/etc)
\\127.0.0.1\c$\Windows\System32\
and executecmd.exe
Input Boxes
Many input boxes accept file paths; try all inputs with UNC paths such as //attacker–pc/
or //127.0.0.1/c$
or C:\
Bypass file restrictions
Enter . or *.exe or similar in File name
box
Internet Explorer
Download and Run/Open
- Text files -> opened by Notepad
Menus
- The address bar
- Search menus
- Help menus
- Print menus
- All other menus that provide dialog boxes
Accessing filesystem
Enter these paths in the address bar:
- file://C:/windows
- C:/windows/
- %HOMEDRIVE%
- \127.0.0.1\c$\Windows\System32
Unassociated Protocols
It is possible to escape a browser based kiosk with other protocols than usual http
or https
.
If you have access to the address bar, you can use any known protocol (irc
, ftp
, telnet
, mailto
, etc.)
to trigger the open with prompt and select a program installed on the host.
The program will than be launched with the uri as a parameter, you need to select a program that will not crash when recieving it.
It is possible to send multiple parameters to the program by adding spaces in your uri.
Note: This technique required that the protocol used is not already associated with a program.
Example - Launching Firefox with a custom profile:
This is a nice trick since Firefox launched with the custom profile may not be as much hardened as the default profile.
- Firefox need to be installed.
- Enter the following uri in the address bar:
irc://127.0.0.1 -P "Test"
- Press enter to navigate to the uri.
- Select the firefox program.
- Firefox will be launched with the profile
Test
.
In this example, it's the equivalent of running the following command:
firefox irc://127.0.0.1 -P "Test"
Shell URI Handlers
A URI (Uniform Resource Identifier) handler is a software component that enables a web browser or operating system to pass a URI to an appropriate application for further handling.
For example, when you click on a "mailto:" link in a webpage, your device knows to open your default email application. This is because the "mailto:" URI scheme is registered to be handled by an email application. Similarly, "http:" and "https:" URIs are typically handled by a web browser.
In essence, URI handlers provide a bridge between web content and desktop applications, allowing for a seamless user experience when navigating between different types of resources.
The following URI handlers might trigger application on the machine:
- shell:DocumentsLibrary
- shell:Librariesshell:UserProfiles
- shell:Personal
- shell:SearchHomeFolder
- shell:System shell:NetworkPlacesFolder
- shell:SendTo
- shell:Common Administrative Tools
- shell:MyComputerFolder
- shell:InternetFolder
References
- PentestPartners - Breaking out of Citrix and other restricted desktop environments
- Breaking Out! of Applications Deployed via Terminal Services, Citrix, and Kiosks - Scott Sutherland - May 22nd, 2013
- Escaping from KIOSKs - HackTricks
- Breaking out of Windows Kiosks using only Microsoft Edge - Firat Acar - May 24, 2022
- HOW TO LAUNCH COMMAND PROMPT AND POWERSHELL FROM MS PAINT - 2022-05-14 - Rickard