SuSE: 'man' format string and other vulnerabilities
Summary
______________________________________________________________________________
SuSE Security Announcement
Package: man
Announcement-ID: SuSE-SA:2001:019
Date: Tuesday, May 29th 2001 20:30 MEST
Affected SuSE versions: 6.0, 6.1, 6.2, 6.3, 6.4, 7.0, 7.1
Vulnerability Type: local privilege escalation
Severity (1-10): 4
SuSE default package: yes
Other affected systems: most linux systems shipping the mandb package
Content of this advisory:
1) security vulnerability resolved: man
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
Two vulnerabilities have been found in the man package that is installed
by default in all SuSE Linux distributions. The first error is a format
string bug in the error handling routine of the man command that can
allow a local attacker to gain the privileges of the user "man" on SuSE
Linux systems (the man command in /usr/bin is installed setuid man).
After getting write access to the /usr/bin/man binary, an attacker can
place a cuckook's egg into the executable, waiting for root to view
manpages.
The second problem is a segmentation fault that can be caused by the
options "-S ::: foo" to the man command. On other Linux distributions,
this problem has been found exploitable. On SuSE and Debian systems, the
code responsible for the bug is different from the one found in other
distributions and is not exploitable. We consider the existence of this
bug a beauty flaw that will be fixed in future releases of the SuSE Linux
distribution, but the fix was not included in the man packages that can
be found on our ftp server.
Since the error() format string bug was discovered earlier than we
announced that the SuSE Linux distributions 6.0, 6.1 and 6.2 will be
discontinued, we also provide fixed packages for the said distributions
for the i386 Intel architecture. We strongly encourage our usership to
upgrade their systems to a newer distribution.
Both bugs are fixed in the upcoming release of SuSE Linux 7.2.
A temporary workaround (as discussed in earlier SuSE security
announcements) is to remove the setuid-bit of the /usr/bin/man file.
This will cause errors to be printed when viewing a manpage, because
the formatted manpages can't be saved to the /var/cache/man directories
any longer. The sideeffects of this workaround are of mostly cosmetical
nature on fast hardware.
If you changed the file modes of the man command binary using the command
chmod 755 /usr/bin/man
, then please also change the occurrences of the same path in the files
/etc/permissions*, provided you have set the variable CHECK_PERMISSIONS
to "set" in /etc/rc.config.
Download the update package from locations described below and check the
authenticity of the rpm package file using a method as described in
section 3) of this security announcement.
Use the command `rpm -Uhv file.rpm' to apply the update.
In some rare cases, the older man package contains files that conflict
with the new version. This should not be considered a problem in this
particular case of the man packge; use the options "--nodeps --force"
to override.
i386 Intel Platform:
SuSE-7.1
bc914ab44fcdeb2fa809176d2b807bea
source rpm:
96dfa2df00ae4a1045c6d038bd02290b
SuSE-7.0
533fa405f82ef5bbcfb4b4a6c188d0da
source rpm:
b935e02d444a613beccec50db65c1cf7
SuSE-6.4
a7cd2aa52a72f739d7c0cac5073f546b
source rpm:
e9fd012fbea95c2787de0ee0612da8ce
SuSE-6.3
807b23473f0813c9c6385d08cc55b698
source rpm:
0ff51500ef8914870cb1785ae3b999b6
SuSE-6.2
edbbe4c94b18802dc23a823d55d59761
source rpm:
eeeed80772476bb306d256e48ad99f95
SuSE-6.1
775db984e6129f10ede2b091bf725f0d
source rpm:
5c4b93a1cf941adeb853bff9263ca3a5
Sparc Platform:
SuSE-7.1
39e097e929dbf4ca7626d5c7dcaf4980
source rpm:
df6900385722e5a7ddae18338eb0ef4c
SuSE-7.0
6c3bda62c576bd92ff7b741a3124e64e
source rpm:
c42b095b229f6b4c45bf7814ae0e1498
AXP Alpha Platform:
SuSE-7.0
3d83a75ff11426bc56fd9663bccee9be
source rpm:
2033a16bc31ec5d81136eabf2508fd6d
SuSE-6.4
f1ee85f46386298748bdb3d76d69e9f2
source rpm:
82792838d464a1fbb14b2c5d79f4d064
SuSE-6.3
5334e0f9efe1de48d7905166ced83c1b
source rpm:
43992649e6ab51000bed5ac4e2f8fcae
PPC Power PC Platform:
SuSE-7.1
5bff5425484c5076023235b3779f22c6
source rpm:
5caba422258827b139e21f6dab7f9b39
SuSE-7.0
832b8078f1c6b2d8d6edae98d26c3d44
source rpm:
4d5647b6276fb6d641410e7eddc106f9
SuSE-6.4
13afa53aacaa939fd1b9dd509d995c2d
source rpm:
2ffd94df5356669d89c1490a326c205d
______________________________________________________________________________
2) Pending vulnerabilities in SuSE Distributions and Workarounds:
- netscape
Netscape before Version 4.77 contains a bug that allows a remote attacker
to store JavaScript code in the comment filed of GIF files that are
contained in a viewed page. This code can be executed.
Update packages for the SuSE Linux distributions 6.3, 6.4, 7.0 and 7.1
can be found on our ftp server at
1e2de825b3386d80a3731760b9e7f323
13f303944c9ac0863591b03c4eb75501
The packages are gpg-signed. See the section above about downloading
and verifying rpm packages.
The complexity of the netscape browser suggests by nature that more
security related problems will be found, we will not issue a dedicated
security announcement for the netscape package any more. Security-
inclined users may please see the future security announcements in
section 2) for information about security related problems with the
netscape package.
- gpg/gnupg
The gpg update package that can be found on our ftp server upgrade your
installation of gpg to the version 1.0.5. We have experienced stability
problems when the turkish locale was used.
We recommened our users to wait for the official SuSE Security
Announcement about gpg/gnupg before performing the upgrade since we
expect more changes to the package.
- pine
Most of the supported distributions have pine update packages in the
update area of the ftp server that update the pine package to version
4.33. Many vulnerabilities have been found in versions before 4.33,
and it is recommended to perform the upgrade.
Please note that not all packages have been built yet. See the update
directory for your distribution (like i386/update/7.0/n1) for pine-4.33
packages.
- dqs
dex@raza-mexicana.org has found an exploitable buffer overflow bug in
the dsh program from the dqs package on SuSE Linux distributions.
To workaround the problem, do "chmod -s /usr/bin/dsh" and change the
files /etc/permissions* to reflect the change. If you do not need the
dqs package, then deinstall it (rpm -e dqs). We are working on update
packages that fix the problem.
- samba
Insecure temporary file handling is the cause for a new samba version
2.0.9 that can be found as rpm packages in the n1/ directory of your
distribution. It is recommended to install the update package if your
users have local shell access to your samba server (this bug is not
remotely exploitable).
We are currently investigating some oddity in the behaviour of the
samba package and will send a security announcement as soon as we
have clarified the problems. The problems were present in earlier
releases/versions of the samba package as well. By consequence, the
installation of the update package is of low risk for the functionality
of your system.
______________________________________________________________________________
3) standard appendix: authenticity verification, additional information
- Package authenticity verification:
SuSE update packages are available on many mirror ftp servers all over
the world. While this service is being considered valuable and important
to the free and open source software community, many users wish to be
sure about the origin of the package and its content before installing
the package. There are two verification methods that can be used
independently from each other to prove the authenticity of a downloaded
file or rpm package:
1) md5sums as provided in the (cryptographically signed) announcement.
2) using the internal gpg signatures of the rpm package.
1) execute the command
md5sum
References
