Er is een gat gevonden in de CVS server. De CVS is vaak aanwezige op de verschillende systemen, als je CVS gebruikt zorg dan dat je je CVS patched.
[quote]
e-matters GmbH
www.e-matters.de
-= Security Advisory =-
Advisory: CVS remote vulnerability
Release Date: 2004/05/19
Last Modified: 2004/05/19
Author: Stefan Esser [s.esser@e-matters.de]
Application: CVS feature release <= 1.12.7 CVS stable release <= 1.11.15 Severity: A vulnerability within CVS allows remote compromise of CVS servers. Risk: Critical Vendor Status: Vendor is releasing a bugfixed version. Reference: http://security.e-matters.de/advisories/072004.html Overview: Concurrent Versions System (CVS) is the dominant open-source version control software that allows developers to access the latest code using a network connection. Stable CVS releases up to 1.11.15 and CVS feature releases up to 1.12.7 both contain a flaw when deciding if a CVS entry line should get a modified or unchanged flag attached. This results in a heap overflow which can be exploited to execute arbitrary code on the CVS server. This could allow a repository compromise. Details: While auditing the CVS source a flaw within the handling of modified and unchanged flag insertion into entry lines was discovered. When the client sends an entry line to the server an additional byte is allocated to have enough space for later flagging the entry as modified or unchanged. In both cases the check if such a flag is already attached is flawed. This allows to insert M or = chars into the middle of a user supplied string one by one for every call to one of these functions. It should be obvious that already the second call could possibly overflow the allocated buffer by shifting the part after the insertion point one char backward. If the alignment of the block is choosen wisely this is already exploitable by malloc() off-by-one exploitation techniques. However carefully crafted commands allow the functions to be called several times to overwrite even more bytes (although this is not really needed if you want to exploit this bug on f.e. glibc based systems). Proof of Concept: e-matters is not going to release an exploit for this vulnerability to the public. Disclosure Timeline: 02. May 2004 - CVS developers and vendor-sec were notified by email Derek Robert Price replied nearly immediately that the issue is fixed 03. May 2004 - Pre-notification process of important repositories was started 11. May 2004 - Sourceforge discovered that the patch breaks compatibility with some pserver protocol violating versions of WinCVS/TortoiseCVS 12. May 2004 - Pre-notified repositories were warned about this problem with a more compatible patch. 19. May 2004 - Coordinated Public Disclosure CVE Information: The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CAN-2004-0396 to this issue. Recommendation: Recommended is an immediate update to the new version. Additionally you should consider running your CVS server chrooted over SSH instead of using the :pserver: method. You can find a tutorial how to setup such a server at http://www.netsys.com/library/papers/chrooted-ssh-cvs-server.txt GPG-Key: http://security.e-matters.de/gpg_key.asc pub 1024D/3004C4BC 2004-05-17 e-matters GmbH - Securityteam Key fingerprint = 3FFB 7C86 7BE8 6981 D1DA A71A 6F7D 572D 3004 C4BC Copyright 2004 Stefan Esser. All rights reserved. [/quote]