[HV-LOW] Symantec LiveUpdate issues may cause DoS
Date: Thu, 4 Nov 2004 15:56:02 -0800 To: email@example.com, firstname.lastname@example.org
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Symantec LiveUpdate issues may cause DoS
Symantec LiveUpdate is an application designed to provide
timely updates for Symantec products. LiveUpdate downloads
zip-archived packages, decompresses them, verifies signatures,
and finally installs the updates. HexView discovered two problems
with LiveUpdate: decompression routine does not check for
uncompressed file sizes and no validation is performed on
HexView tested the issue using LiveUpdate versions 220.127.116.11 and
18.104.22.168 running on Windows XP SP1. Probably all other LiveUpdate
versions are vulnerable.
Cause and Effect:
After downloading ZIP archive off the website (either legitimate
Symantec website or a spoofed one controlled by attacker)
LiveUpdate starts decompressing a set of files it expects to
find in an archive. LiveUpdate does not perform uncompressed file
size validation, so it is possible to cause an effective DoS by
forcing LiveUpdate to decompress an extremely large file that will
consume all available hard drive space. This issue is known as
LiveUpdate also decompresses a directory tree without validation
of directory names. Directory traversal is possible through ".."
meaning that LiveUpdate can be forced to create a directory anywhere
on the current disk. While LiveUpdate will not overwrite existing
files, this issue can be exploited to mount a DoS attack against
applications by creating a directory using the name of the file that
victim application is expected to create. Once such directory is
created, the application will fail to create the file which will
cause unpredictable results.
LiveUpdate 1.80.19 cleans up after itself, but it only deletes
files, not directories. LiveUpdate 2.5.56 does not delete files
when failure occurs.
It is possible to repackage Symantec's legitimate archives so they
will be cleanly processed by LiveUpdate and the fact of attack will
not be noticed.
Symantec was notified on 2004-11-03. No response received.
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