iSEC Partners Security Advisory - 2007-001-vlc
http://www.isecpartners.com
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VLC 0.8.6b format string vulnerability & integer overflow

Vendor: VideoLan
Vendor URL: http://www.videolan.org
Systems Affected: Confirmed on Windows XP, FreeBSD 6.2, MacOS X 10.4
Severity: High (memory access violations, potential code execution)
Author: David Thiel <david [at] isecpartners.com>

Vendor notified: 2007-06-05
Public release: 2007-06-21
Advisory URL: http://www.isecpartners.com/advisories/2007-001-vlc.txt
Vendor Advisory: http://www.videolan.org/sa0702.html

Summary:
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VLC is vulnerable to a format string attack in the parsing of Vorbis
comments in Ogg Vorbis and Ogg Theora files, CDDA data or SAP/SDP
service discovery messages. Additionally, there are two errors in the
handling of wav files, one a denial of service due to an uninitialized
variable, and one integer overflow in sampling frequency calculations.

Details:
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The input_vaControl function in input.c calls vasprintf() with an
externally-supplied format string, as specified in the value of a Vorbis
comment. This can lead to arbitrary code execution.

An excessively large sample rate causes an integer overflow, resulting
in a SEGV in __status_Update in stats.c.

An uninitialized i_nb_resamplers in input.c can cause a crash during 
audio stream processing.

Fix Information:
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These issues are fixed version 0.8.6c. Workarounds for previous versions
are documented in the vendor advisory.

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