dcsimg
Linux Today: Linux News On Internet Time.




More on LinuxToday


SuSE Security Announcement: ypbind/ypclient

Oct 18, 2000, 20:26 (0 Talkback[s])
(Other stories by Roman Drahtmueller)

Date: Wed, 18 Oct 2000 19:22:36 +0200 (MEST)
From: Roman Drahtmueller draht@suse.de
To: suse-security-announce@suse.de
Subject: [suse-security-announce] SuSE Security Announcement: ypbind/ypclient (SuSE-SA:2000:042)


                        SuSE Security Announcement

        Package:                ypbind/ypclient
        Announcement-ID:        SuSE-SA:2000:042
        Date:                   Wednesday, October 18th, 2000 19:15 MEST
        Affected SuSE versions: 6.0, 6.1, 6.2, 6.3, 6.4, 7.0
        Vulnerability Type:     possible remote root compromise
        Severity (1-10):        8
        SuSE default package:   yes (starting with SuSE-6.4)
        Other affected systems: Linux systems using this NIS implementation

    Content of this advisory:
        1) security vulnerability resolved: ypbind/ypclient
           problem description, discussion, solution and upgrade information
        2) pending vulnerabilities, solutions, workarounds
        3) standard appendix (further information)

1) problem description, brief discussion, solution, upgrade information

Security problems have been found in the client code of the NIS (Network Information System, aka yp - yellow pages) subsytem. SuSE distributions before SuSE-6.1 came with the original ypbind program, SuSE-6.2 and later included the ypbind-mt NIS client implementation. ypbind-3.3 (the earlier version) has a format string parsing bug if it is run in debug mode, and (discovered by Olaf Kirch ) leaks file descriptors under certain circumstances which can lead to a DoS. In addition, ypbind-3.3 may suffer from buffer overflows.

ypbind-mt, the software shipped with SuSE distributions starting with SuSE-6.2, suffers from a single format string parsing bug. Some of these bugs could allow remote attackers to execute arbitrary code as root.

During code audit and testing it turned out that the ypbind-3.x software in the SuSE-6.1 distribution and earlier needs a major overhaul to make it work both reliable and secure with respect to errors in the code. Basically, this is what happened when Thorsten Kukuk wrote ypbind-mt from scratch in 1998. For the same reason, we are currently unable to produce a working security update package which fixes the known and yet unknown (there may be more) problems in the ypclient packages in the SuSE-6.1 distribution and older.

The only efficient workaround for the SuSE-6.1 distribution and older against these bugs for an untrusted, hostile environment is to upgrade to a new distribution base (SuSE-7.0 is recommended) and use the ypclient update packages for this distribution.

As of today, there is no exploit known to exist in the wild.

For SuSE-6.2 and later distributions we provide update packages as listed below. We recommend to download and install these packages on systems that are NIS/yp clients.

Please note that the sources for the ypclient package are contained within the ypserv source rpm.

Download the update package from locations described below and install the package with the command `rpm -Uhv file.rpm'. The md5sum for each file is in the line below. You can verify the integrity of the rpm files using the command `rpm --checksig --nogpg file.rpm', independently from the md5 signatures below.

i386 Intel Platform:

SuSE-7.0
ftp://ftp.suse.com/pub/suse/i386/update/7.0/n1/ypclient-3.5-89.i386.rpm
76e4e7f60791db16c5e36fb5dbf60b65
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/ypserv-1.3.11-89.src.rpm
e2b1dccaec003f54e4ebbdef84d99a10

SuSE-6.4
ftp://ftp.suse.com/pub/suse/i386/update/6.4/n1/ypclient-3.4-95.i386.rpm
e485ea27264fb9c4f890cdf7605ffa30
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.4/zq1/ypserv-1.3.11-95.src.rpm
c61c6df2ba1fef2369406b2dcbcd25f1

SuSE-6.3
ftp://ftp.suse.com/pub/suse/i386/update/6.3/n1/ypclient-3.4-95.i386.rpm
c1a10cc0a3f72242b136be921f9ae0c1
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.3/zq1/ypserv-1.3.11-95.src.rpm
6f47a880d5e7175dc2b5ff0116d7de4d

SuSE-6.2
ftp://ftp.suse.com/pub/suse/i386/update/6.2/n1/ypclient-3.4-95.i386.rpm
9050e63cb9f7fac4997968760292a6f1
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.2/zq1/ypserv-1.3.11-95.src.rpm
7ecfaffd8cdb68f73adfd1d6fd27ed39

SuSE-6.1 and older:
Please see the problem description above.

Sparc Platform:

SuSE-7.0
ftp://ftp.suse.com/pub/suse/sparc/update/7.0/n1/ypclient-3.5-89.sparc.rpm
1a38d25c8647f010e2a9879f28de4adf
source rpm:
ftp://ftp.suse.com/pub/suse/sparc/update/7.0/zq1/ypserv-1.3.11-89.src.rpm
6ba9200e49210f98ca845107b034b981

AXP Alpha Platform:

SuSE-6.4
ftp://ftp.suse.com/pub/suse/axp/update/6.4/n1/ypclient-3.4-95.alpha.rpm
6aea95ca27245eb3df72da7596af3321
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/6.4/zq1/ypserv-1.3.11-95.src.rpm
a4bf635b9ee4bdefc29b7e6e1cf0cf41

SuSE-6.3
ftp://ftp.suse.com/pub/suse/axp/update/6.3/n1/ypclient-3.4-95.alpha.rpm
b68f8690b7dc554ac9098c83f9c633cd
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/6.3/zq1/ypserv-1.3.11-95.src.rpm
ef0a026d078847d0958118bbbc46b99e

PPC Power PC Platform:

SuSE-6.4
ftp://ftp.suse.com/pub/suse/ppc/update/6.4/n1/ypclient-3.4-95.ppc.rpm
26080b1443a3daa1de64c876ae36e6f2
source rpm:
ftp://ftp.suse.com/pub/suse/ppc/update/6.4/zq1/ypserv-1.3.11-95.src.rpm
4f0904d73c98c8b9737d5ac34b7a4dd5


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

Another security announcement is following this advisory.


3) standard appendix:

SuSE runs two security mailing lists to which any interested party may subscribe:

suse-security@suse.com
- general/linux/SuSE security discussion.
All SuSE security announcements are sent to this list. To subscribe, send an email to suse-security-subscribe@suse.com.

suse-security-announce@suse.com
- SuSE's announce-only mailing list.
Only SuSE's security annoucements are sent to this list. To subscribe, send an email to suse-security-announce-subscribe@suse.com.

For general information or the frequently asked questions (faq) send mail to:
suse-security-info@suse.com or
suse-security-faq@suse.com respectively.


SuSE's security contact is security@suse.com.


Regards,
Roman Drahtmüller.
- - --

 -                                                                      -
| Roman Drahtmüller        draht@suse.de //          "Caution: Cape does |
  SuSE GmbH - Security           Phone: //       not enable user to fly."
| Nürnberg, Germany     +49-911-740530 // (Batman Costume warning label) |
 -                                                                      -