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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.219 -- FreeBSD-SA-00:37 cvsweb allows increased access to CVS committers 17 August 2000 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: cvsweb Vendor: FreeBSD Ports Collection Operating System: FreeBSD Linux Unix Platform: N/A Impact: Execute Arbitrary Code/Commands Access Required: Remote - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- ============================================================================= FreeBSD-SA-00:37 Security Advisory FreeBSD, Inc. Topic: cvsweb allows increased access to CVS committers Category: ports Module: cvsweb Announced: 2000-08-14 Credits: Joey Hess <firstname.lastname@example.org> Affects: Ports collection prior to the correction date. Corrected: 2000-07-11 Vendor status: Patch released FreeBSD only: NO I. Background cvsweb is a CGI script which provides a read-only interface to a CVS repository for browsing via a web interface. II. Problem Description The cvsweb port, versions prior to 1.86, contains a vulnerability which allows users with commit access to a CVS repository monitored by cvsweb to execute arbitrary code as the user running the cvsweb.cgi script, which may be located on another machine where the committer has no direct access. The vulnerability is that cvsweb does not correctly process input obtained from the repository and is vulnerable to embedding of commands in committed filenames. Such an action is however usually highly visible in the CVS repository and provides an audit trail of sorts for such abuses unless the committer has access to modify the repository files directly to cover his or her tracks. This vulnerability may or may not be a security issue depending on the local security policy (for example, CVS itself is known to easily allow committers to execute commands on the CVS server even without a login account, so this presents little additional exposure if cvsweb is run on the CVS server itself). The cvsweb port is not installed by default, nor is it "part of FreeBSD" as such: it is part of the FreeBSD ports collection, which contains nearly 3700 third-party applications in a ready-to-install format. The ports collections shipped with FreeBSD 3.5 contains this problem since it was discovered after the release, but it was fixed prior to the release of FreeBSD 4.1. FreeBSD makes no claim about the security of these third-party applications, although an effort is underway to provide a security audit of the most security-critical ports. III. Impact CVS committers can execute code as the user running the cvsweb.cgi script, which may present a violation of local security policy. If you have not chosen to install the cvsweb port/package, then your system is not vulnerable to this problem. IV. Workaround Deinstall the cvsweb port/package, if you you have installed it. V. Solution One of the following: 1) Upgrade your entire ports collection and rebuild the cvsweb port. 2) Deinstall the old package and install a new package dated after the correction date, obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/cvsweb-188.8.131.52.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/cvsweb-184.108.40.206.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/cvsweb-220.127.116.11.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/cvsweb-18.104.22.168.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/cvsweb-22.214.171.124.tgz NOTE: It may be several days before updated packages are available. 3) download a new port skeleton for the cvsweb port from: http://www.freebsd.org/ports/ and use it to rebuild the port. 4) Use the portcheckout utility to automate option (3) above. The portcheckout port is available in /usr/ports/devel/portcheckout or the package can be obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz - -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBOZh1qlUuHi5z0oilAQEAjAP7B+Kss7dLQ3upyq8HLwVMr5fhOPgW6TWK BtkZ71mBapFQleZi9vWbpd/R2Cow7i42nsZQi8d7kERiXJRW6EGXr125aIA5NopV 1NoR4BKa9KYOP0CI9jqYUWiMj5PfNy03HlLbrDzHbGOIbqMqcsERXEFNGvt0Qvb4 qkjHlQ9faRE= =VajH - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. 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Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: email@example.com 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 emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBOaD01yh9+71yA2DNAQEXngP+LRWe9bXmn7ZEvzUdH1yCp5HqS1wc9bUq E9u/WgqKt7A8FdrBfxwGJzw+u58rVi4MxKq+P3TUFtbbvu9Wga41F7eo4uAGhUQ1 vz7CrDmwKZ6/qjEQnDisx22VETFUxbJ/xSktDOaC4S8iIu5Bkcr6AtVSwF0cAGkA nzjwE7yf8MY= =qZRZ -----END PGP SIGNATURE-----