[Full-disclosure] kpopper insecure temporary file creation

[ZATAZ Audits]

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kpopper insecure temporary file creation

Vendor: http://kpopper.sourceforge.net/
Advisory: http://www.zataz.net/adviso/kpopper-06152005.txt
Vendor informed: yes
Exploit available: yes
Impact : low
Exploitation : low

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The vulnerability is caused due to temporary file being created insecurely.
This can be exploited via symlink attacks in combination  to create and 
overwrite arbitrary files with the privileges of the user running the 
affected script.

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Versions:
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kpopper <= 1.0

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Solution:
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To prevent symlink attack use kernel patch such as grsecurity

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Timeline:
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Discovered : 2005-06-13
Vendor notified : 2005-06-15
Vendor response : no reponse
Vendor fix : no fix
Vendor Sec report (vendor-sec at lst.de) : 2005-06-27
Disclosure : 2005-07-04

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Technical details :
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Vulnerable code :
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popper/popper-send.sh

#!/bin/sh
echo "$2" > /tmp/.popper-new
echo `date +"%a %l:%m %p"` >> /tmp/.popper-new
cat "$1" >> /tmp/.popper-new
mv -f /tmp/.popper-new /tmp/.popper

The .popper is also used into :

popper/popper.cpp

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Related :
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Bug report : http://bugs.gentoo.org/show_bug.cgi?id=94475
CVE : CAN-2005-1917

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Credits :
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Eric Romang (eromang at zataz.net - ZATAZ Audit)
Thxs to Gentoo Security Team. (Taviso, jaervosz, solar, etc.)