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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2010.0201 KDE Security Advisory: KRunner lock module race condition 25 February 2010 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: KDE 4.4.0 Publisher: KDE Operating System: UNIX variants (UNIX, Linux, OSX) Impact/Access: Unauthorised Access -- Console/Physical Resolution: Patch/Upgrade Original Bulletin: http://www.kde.org/info/security/advisory-20100217-1.txt - --------------------------BEGIN INCLUDED TEXT-------------------- KDE Security Advisory: KRunner lock module race condition Original Release Date: 2010-02-17 URL: http://www.kde.org/info/security/advisory-2010-02-17-1.txt 0. References oCert: N/A CVE: N/A 1. Systems affected: KDE 4.4.0 is the only version affected. 2. Overview: KRunner lock module race condition: The KRunner lock module forks a process to perform password validation. This forking process does not properly check whether an existing process has already been forked, creating a race condition if the Enter key is pressed after a process has been forked but before the password has been validated. In this case, multiple processes can be forked, causing a socket listener on the parent to point to either an incorrect process that has not received the password data, resulting in a hang, or in some cases cause the socket notifier to point to an already-deleted object, resulting in a crash that brings the user to the desktop and circumvents the lock mechanism. Note: the locking is actually performed by KRunner, which is part of the kdebase module, and not KScreenSaver; even when no screen saver is being used an affected system can still be compromised. 3. Impact: This is a critical vulnerability that is easily exploited if physical access to a machine is granted, and can result in an attacker gaining full privileges of the user whose screen is currently locked. 4. Solution: Source code patches have been made available which fix these vulnerabilities. OS vendors / binary package providers have been contacted and in most cases a patched version should already be available. Contact your OS vendor / binary package provider for information about how to obtain updated binary packages or for information about which version of the package contains the patch. 5. Patch: Patches for KDE 4.4.0 have been committed to Subversion, and are available from websvn.kde.org: http://websvn.kde.org/?view=rev&revision=1089241 A patch may also be obtained directly from the Subversion repository (no checkout needed) with the following command: svn diff -r 1089240:1089241 \ svn://anonsvn.kde.org/home/kde/branches/KDE/4.4/kdebase/workspace/krunner/lock - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iD8DBQFLhfMb/iFOrG6YcBERAnkaAJ0QdXg2sqOh8NAcvNUEjMdqkEV/+ACeIM1z 05OpCrlMWfTpY7UJtbh2Vpw= =T8WN -----END PGP SIGNATURE-----