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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2005.0749 -- TWiki INCLUDE function allows arbitrary shell command execution 29 September 2005 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: TWiki Publisher: UNIRAS Operating System: UNIX variants Windows Mac OS Impact: Execute Arbitrary Code/Commands Access: Remote/Unauthenticated CVE Names: CAN-2005-3056 Original Bulletin: http://twiki.org/cgi-bin/view/Codev/SecurityAlertExecuteCommandsWithInclude - --------------------------BEGIN INCLUDED TEXT-------------------- Title ===== TWiki - TWiki INCLUDE function allows arbitrary shell command execution Detail ====== UNIRAS COMMENT - Please note that the patches discussed in this advisory are not attached to this briefing, but are available from the first URL below. This advisory alerts you of a potential security issue with your TWiki installation: The TWiki INCLUDE function allows arbitrary shell command execution. The permanent place for this advisory is http://twiki.org/cgi-bin/view/Codev/SecurityAlertExecuteCommandsWithInclude where you can see updates and follow-ups. If you do not use TWiki, please ignore this e-mail. If you don't administer your TWiki site, or started a site now administered by someone else, please pass it to the current TWiki site administrator. Please see also unrelated security audit on visible lib directories, http://twiki.org/cgi-bin/view/Codev/SecurityAuditOnVisibleLibDir Table of Contents: * Vulnerable Software Version * Attack Vectors * Impact * MITRE Name for this Vulnerability * Details * Countermeasures * Authors and Credits * Hotfix * Patch for TWiki Production Release 03-Sep-2004 * Patch for TWiki Production Release 02-Sep-2004 * Patch for TWiki Production Release 01-Feb-2003 * TWiki News - - ---++ Vulnerable Software Version * TWikiRelease03Sep2004[2] -- TWiki20040903.zip * TWikiRelease02Sep2004[3] -- TWiki20040902.zip * TWikiRelease01Sep2004[4] -- TWiki20040901.zip * TWikiRelease01Feb2003[5] -- TWiki20030201.zip Not affected are: * Recent DakarReleases[6] (upcoming production release, soon) * TWikiRelease01Sep2004 patched with Florian Weimer's UncoordinatedSecurityAlert23Feb2005[7] - - ---++ Attack Vectors Editing wiki pages and HTTP GET requests towards the Wiki server (typically port 80/TCP). Typically, prior authentication is necessary (including anonymous TWikiGuest accounts). - - ---++ Impact An attacker is able to execute arbitrary shell commands with the privileges of the web server process, such as user nobody. - - ---++ MITRE Name for this Vulnerability The Common Vulnerabilities and Exposures project has assigned the name CAN-2005-3056 to this vulnerability. - - ---++ Details The TWiki INCLUDE function enables a malicious user to compose a command line executed by the Perl backtick (``) operator. The rev parameter of the INCLUDE variable is not checked properly for shell metacharacters and is thus vulnerable to revision numbers containing pipes and shell commands. The exploit is possible on included topics with two or more revisions. Example INCLUDE variable exploiting the rev parameter: %INCLUDE{ "Main.TWikiUsers" rev="2|less /etc/passwd" }% The same vulnerability is exposed to all Plugins and add-ons that use TWiki::Func::readTopicText[8] function to read a previous topic revision. This has been tested on TWiki:Plugins.RevCommentPlugin[9] and TWiki:Plugins.CompareRevisionsAddon[10]. If access to TWiki is not restricted by other means, attackers can use the revision function with or without prior authentication, depending on the configuration. See Also: * IncludePreviousTopicRevision[11] * SecurityAlertExecuteCommandsWithRev[12] * SecurityAlertExecuteCommandsWithSearch[13] * UncoordinatedSecurityAlert23Feb2005[7] - - ---++ Countermeasures * Apply hotfix (see patches below) * NOTE: The hotfix is known to prevent the current attacks, but it might not be a complete fix * Upgrade to the latest patched production TWikiRelease04Sep2004[1] * NOTE: If you are running an *unmodified* TWikiRelease01Sep2004[4], TWikiRelease02Sep2004[3] or TWikiRelease03Sep2004[2], simply copy the following patched files from TWikiRelease04Sep2004 to your installation: lib/TWiki.pm, lib/TWiki/Store.pm, lib/TWiki/UI/RDiff.pm, lib/TWiki/UI/View.pm, lib/TWiki/UI/Viewfile.pm * Apply patch of UncoordinatedSecurityAlert23Feb2005[7] (but see known issues of that patch) * Filter access to the web server * Use the web server software to restrict access to the web pages served by TWiki - - ---++ Authors and Credits * Credit to TWiki:Main.JChristophFuchs (jcf@ipp.mpg.de) and TWiki:Main.JoseLuna (luna@aditel.org) for disclosing the issue to the twiki-security@lists.sourceforge.net mailing list * TWiki:Main.JoseLuna for contributing a more robust patch to recent SecurityAlertExecuteCommandsWithRev[12] issue (included in this patch) * TWiki:Main.PeterThoeny, TWiki:Main.JoseLuna, TWiki:Main.CrawfordCurrie for contributing to the advisory and the patch - - ---++ Hotfix - - ---+++ Patch for TWiki Production Release 03-Sep-2004 Affected files: twiki/lib/TWiki.pm, twiki/lib/TWiki/Store.pm, lib/TWiki/UI/RDiff.pm, lib/TWiki/UI/View.pm, lib/TWiki/UI/Viewfile.pm See attached patch file TWiki200409-03-04patch.txt - - ---+++ Patch for TWiki Production Release 02-Sep-2004 Affected files: twiki/lib/TWiki.pm, twiki/lib/TWiki/Store.pm, lib/TWiki/UI/RDiff.pm, lib/TWiki/UI/View.pm, lib/TWiki/UI/Viewfile.pm See attached patch file TWiki200409-02-04patch.txt - - ---+++ Patch for TWiki Production Release 01-Feb-2003 __Note:__ This assumes that the release is already patched with SecurityAlertExecuteCommandsWithRev[12] fix. Affected files: twiki/lib/TWiki/Store.pm, twiki/bin/rdiff, twiki/bin/view, twiki/bin/viewfil= See attached patch file TWiki200302-01-04patch.txt - - ---++ TWiki News * A new TWiki release is upcoming soon, code named DakarRelease[6] * To customize your TWiki installation, TWiki.org offers now 177 Plugin packages[14], 56 Add-on packages[15], 30 Skin packages[16], and 11 TWiki contrib packages [17] * Codev.TWikiSecurityAlertProcess[18] documents our security process * Wikis and TWiki get covered more my the press[19] * TWiki is represented at the International Symposium on Wikis[20] in San Diego, 17-18 Oct 2005 * A new book on Wikis in the Workplace is in work[21] Best regards, Peter [1]: http://twiki.org/cgi-bin/view/Codev/TWikiRelease04Sep2004 [2]: http://twiki.org/cgi-bin/view/Codev/TWikiRelease03Sep2004 [3]: http://twiki.org/cgi-bin/view/Codev/TWikiRelease02Sep2004 [4]: http://twiki.org/cgi-bin/view/Codev/TWikiRelease01Sep2004 [5]: http://twiki.org/cgi-bin/view/Codev/TWikiRelease01Feb2003 [6]: http://twiki.org/cgi-bin/view/Codev/DakarReleases [7]: http://twiki.org/cgi-bin/view/Codev/UncoordinatedSecurityAlert23Feb2005 [8]: http://twiki.org/cgi-bin/view/TWiki/TWikiFuncModule [9]: http://twiki.org/cgi-bin/view/Plugins/RevCommentPlugin [10]: http://twiki.org/cgi-bin/view/Plugins/CompareRevisionsAddon [11]: http://twiki.org/cgi-bin/view/Codev/IncludePreviousTopicRevision [12]: http://twiki.org/cgi-bin/view/Codev/SecurityAlertExecuteCommandsWithRev [13]: http://twiki.org/cgi-bin/view/Codev/SecurityAlertExecuteCommandsWithSearch [14]: http://twiki.org/cgi-bin/view/Plugins/PluginPackage [15]: http://twiki.org/cgi-bin/view/Plugins/AddOnPackage [16]: http://twiki.org/cgi-bin/view/Plugins/SkinPackage [17]: http://twiki.org/cgi-bin/view/Plugins/ContribPackage [18]: http://twiki.org/cgi-bin/view/Codev/TWikiSecurityAlertProcess [19]: http://twiki.org/cgi-bin/view/Codev/TWikiInTheNews [20]: http://twiki.org/cgi-bin/view/Codev/InternationalSymposiumOnWikis [21]: http://twiki.org/cgi-bin/view/Codev/WikisInTheWorkplaceBook - --------------------------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 iQCVAwUBQztgVCh9+71yA2DNAQJQEQP9HRTyzJBudOGSS/lUSUq4jAYWSpUq0BL2 60r6oLqbz3DMEy35O+DrOQUrjOd7SgEQePT87yZPvOChKLAJxkIU3INarDUBYaCf kAkNzGFOWBAECnJ9TNli+KmmIjOR231Dmc70qfvYtz2pQH2fv9kBKZI5nqsAfLp6 dmwxucZxSrg= =8SYk -----END PGP SIGNATURE-----