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Summary: By a user receiving data from a malicious network streaming server, an attacker can overrun a heap buffer, which can, on some systems, lead to or help in executing attacker-chosen malicious code with the permissions of the user running a xine-lib based media application.
Description: Both the MMS and Real RTSP streaming client code made some too strong assumptions on the transfered data. Several critical bounds checks were missing, resulting in the possibility of heap overflows, should the remote server not adhere to these assumptions. In the MMS case, a remote server could present content with too many individual streams, in the RTSP case, a remote server's reply could have too many lines. An attacker can setup a server delivering malicious data to the users. This can be used to overflow a heap buffer, which can, with certain implementations of heap management, lead to attacker chosen data written to the stack. This can cause attacker-chosen code being executed with the permissions of the user running the application. By tricking users to retrieve a stream, which can be as easy as providing a link on a website, this vulnerability can be exploited remotely.
Severity: This is difficult to exploit remotely, because the indirection involved requires precision and knowledge of the target machine: The heap overlow needs to alter heap management information in a way so that a return adress on the stack is modified. This adress must lead to some malicious code to be executed, which needs to be injected somehow. The involved xine plugin is part of the standard xine installation, so we consider this problem to be moderately severe.
Affected versions: All 0.9 releases starting with and including 0.9.9 All 1-alpha releases. All 1-beta releases. All 1-rc releases. The 1.0 release.
Unaffected versions: All releases older than 0.9.9. 1.0.1 or newer.
Solution: The enclosed patches which have been applied to xine-lib CVS fix the problem but should only be used by distributors who do not want to upgrade. Otherwise, we strongly advise everyone to upgrade to the soon to arrive 1.0.1 release of xine-lib. As a temporary workaround, you may delete the files "xineplug_inp_mms.so" and "xineplug_inp_rtsp.so" from the xine-lib plugin directory, losing the ability to use MMS or Real RTSP streaming content.
Patches: http://cvs.sourceforge.net/viewcvs.py/xine/xine-lib/src/input/librtsp/rtsp.c?r1=1.18&r2=1.19&diff_format=u http://cvs.sourceforge.net/viewcvs.py/xine/xine-lib/src/input/mms.c?r1=1.55&r2=1.56&diff_format=u
For further information and in case of questions, please contact the xine team. Our website is http://xinehq.de/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux)
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