Crash in Zoidcom 1.0 beta 4
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Luigi Auriemma
Application: Zoidcom
http://www.zoidcom.com
Versions: <= 1.0 beta 4
Platforms: Windows and Linux
Bug: access to unallocated memory
Exploitation: remote, versus server and clients
Date: 10 May 2005
Author: Luigi Auriemma
e-mail: aluigi@xxxxxxxxxxxxx
web: http://aluigi.altervista.org
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1) Introduction
2) Bug
3) The Code
4) Fix
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1) Introduction
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Zoidcom in an UDP network library developed by Jörg Rüppel.
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2) Bug
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The first 4 bytes at the beginning of any UDP packet handled by this
library specify the size of the packet data in bits.
When a packet is received the library calls the
ZCom_BitStream::Deserialize function that allocates a target buffer of
the size specified in these 4 bytes and then copies all the subsequent
part of the packet in it.
If an attacker specifies a big amount of bits the Deserialize()
function will try to read the unallocated memory located after
the packet buffer or the library will exit immediately if the amount of
bits is so big that the target buffer cannot be allocated.
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3) The Code
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http://aluigi.altervista.org/poc/zoidboom.zip
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4) Fix
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1.0 beta 5
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Luigi Auriemma
http://aluigi.altervista.org