[Fwd: FreeBSD Security Advisory FreeBSD-SA-03:01.cvs]

Hi, maybe this can be of interest for the admins of cvs.php.net bye, -------- Original Message -------- Subject: FreeBSD Security Advisory FreeBSD-SA-03:01.cvs Date: Tue, 4 Feb 2003 10:46:34 -0800 (PST) From: FreeBSD Security Advisories <security-advisories@freebsd.org> Reply-To: security-advisories@freebsd.org To: FreeBSD Security Advisories <security-advisories@freebsd.org> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =============================================================================

FreeBSD-SA-03:01.cvs                                        Security Advisory
                                                          The FreeBSD Project

Topic:          remotely exploitable vulnerability in cvs server

Category:       contrib
Module:         contrib_cvs
Announced:      2003-02-04
Credits:        Stefan Esser <s.esser@e-matters.de>
Affects:        All FreeBSD versions prior to 4.6-RELEASE-p7, 4.7-RELEASE-p4,
                5.0-RELEASE-p1
Corrected:      2003-01-21 22:26:46 UTC (RELENG_4)
                2003-02-04 18:05:07 UTC (RELENG_5_0)
                2003-02-04 18:07:20 UTC (RELENG_4_7)
                2003-02-04 18:08:26 UTC (RELENG_4_6)

FreeBSD only: NO I. Background The Concurrent Versions System (CVS) is a version control system. It may be used to access a repository locally, or to access a `remote repository' using several different methods, including `ext' (rsh), and `pserver' (password-authenticated server). When accessing a remote repository, the target machine runs the CVS server to fulfill client requests. II. Problem Description The implementation of the CVS server contains a programming error which can lead to a block of memory being freed more than once (i.e. a double-free bug). Separately, the CVS server allows clients with write access to specify arbitrary commands to execute as part of an update (update-prog) or commit (checkin-prog). This is a dangerous feature that is generally not needed: there are other, safer methods of triggering program execution. III. Impact An attacker may exploit the double-free bug in order to bypass write access checks. Combined with the update-prog/checkin-prog feature, the attacker may be able to execute arbitrary commands with the privileges of the CVS server. The impact is most severe when running the CVS server in `pserver' mode to provide read-only access to the world (anoncvs). IV. Workaround Do not use `pserver' mode directly. Instead, use one of the safer methods described in the following online resources: <URL:http://openbsd.sunsite.ualberta.ca/papers/anoncvs-paper.ps> <URL:http://www.netsys.com/library/papers/chrooted-ssh-cvs-server.txt> V. Solution 1) Upgrade your vulnerable system to 4.7-STABLE; or to the RELENG_4_7 (4.7-RELEASE-p4), RELENG_4_6 (4.6-RELEASE-p7), or RELENG_5_0 (5.0-RELEASE-p1) security branch dated after the correction date. 2) To patch your present system: The following patch has been verified to apply to FreeBSD 4.6, 4.7, and 5.0 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:01/cvs.patch # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:01/cvs.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/gnu/usr.bin/cvs # make obj && make depend && make && make install VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD.

Path                                                             Revision

Branch - ------------------------------------------------------------------------- src/contrib/cvs/src/server.c

  RELENG_5_0                                                     1.17.2.1
  RELENG_4_7                                                 1.13.2.2.6.1
  RELENG_4_6                                                 1.13.2.2.4.1

- ------------------------------------------------------------------------- VII. References <URL:http://online.securityfocus.com/archive/1/72584> <URL:http://security.e-matters.de/advisories/012003.html> <URL:http://ccvs.cvshome.org/servlets/NewsItemView?newsID=51> <URL:http://www.kb.cert.org/vuls/id/650937> -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (FreeBSD) iD8DBQE+QAU9FdaIBMps37IRAvYzAKCeaZ1eWwiWNxRqgNRwnn4TwuwPPACdGF8T 0Ym2kCQxU0sJSRxmgAA/yM4= =9+5m -----END PGP SIGNATURE----- This is the moderated mailing list freebsd-announce. The list contains announcements of new FreeBSD capabilities, important events and project milestones. See also the FreeBSD Web pages at http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-announce" in the body of the message -- ------------------------------- ------------------------------------- Michael Bretterklieber - Michael.Bretterklieber@jawa.at JAWA Management Software GmbH - http://www.jawa.at Liebenauer Hauptstr. 200 -------------- privat --------------- A-8041 GRAZ GSM: ++43-(0)676-93 96 698 Tel: ++43-(0)316-403274-12 E-mail: michael@bretterklieber.com Fax: ++43-(0)316-403274-10 http://www.bretterklieber.com ------------------------------- ------------------------------------- "...the number of UNIX installations has grown to 10, with more expected..." - Dennis Ritchie and Ken Thompson, June 1972