Red Hat Linux Security Advisory
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Synopsis	glibc local write access vulnerability

Advisory ID	RHSA-2001:002-03

Issue Date	2001-01-15

Updated On	2001-01-16

Product	Red Hat Linux

Keywords	glibc LD_PRELOAD SEGFAULT_OUTPUT_NAME

Cross References

Obsoletes

1. Topic:

A bug in GNU C Library allows unprivileged user to preload libraries
located in /lib or /usr/lib directories into SUID programs even if those
libraries have not been marked as such by system administrator.

2. Problem description:

LD_PRELOAD variable is honoured normally even for SUID/SGID applications
(but removed afterwards from environment) if it does not contain `/'
characters, but there is a special check which only preloads found
libraries if they have the SUID bit set. However, if a library has been
found
in /etc/ld.so.cache, this check was not performed. As a result, a
malicious user
could preload some /lib or /usr/lib library before SUID/SGID application
and create or overwrite a file he did not have permissions to.
Also, LD_PROFILE output from SUID programs would go into /var/tmp,
making it vulnerable to various link attacks.

3. Bug IDs fixed: (see bugzilla for more information)

20832 - Unknown system type Nautilus

4. Relevant releases/architectures:

Red Hat Linux 6.0 - alpha, i386, sparc, sparcv9
Red Hat Linux 6.1 - alpha, i386, sparc, sparcv9
Red Hat Linux 6.2 - alpha, i386, sparc, sparcv9

5. RPMs required:

6. Solution:

For each RPM for your particular architecture, run:

rpm -Fvh [filename]

where filename is the name of the RPM.

7. Verification:

MD5 sum                           Package Name
-------------------------------------------------------------------------
ef78f44366467486a0dac8794bc17ab9  6.2/en/os/SRPMS/glibc-2.1.3-22.src.rpm
b860e2f939f4e6517f4672361d746b38  6.2/en/os/i386/nscd-2.1.3-22.i386.rpm
e9b9b581fa4eda1a9aa2a5de8b267889  6.2/en/os/i386/glibc-profile-2.1.3-22.i386.rpm
2a779a3f6c3b87059cf40686f55dc2f6  6.2/en/os/i386/glibc-devel-2.1.3-22.i386.rpm
b841df797bf42585476f30b1ba489e30  6.2/en/os/i386/glibc-2.1.3-22.i386.rpm
e768b72385324280d62b271895261021  6.2/en/os/alpha/nscd-2.1.3-22.alpha.rpm
57040728348767ef4475ab82091a3db0  6.2/en/os/alpha/glibc-profile-2.1.3-22.alpha.rpm
e5a7cf85e50c599a51e7b9ee7d1bc78d  6.2/en/os/alpha/glibc-devel-2.1.3-22.alpha.rpm
c1edf134c6d5790ce74d7c4272ec8687  6.2/en/os/alpha/glibc-2.1.3-22.alpha.rpm
1de8f29192f62e1cc33f76d920e20a1a  6.2/en/os/sparcv9/glibc-2.1.3-22.sparcv9.rpm
966d69ca5182a97315e1f7bf5a5b7c30  6.2/en/os/sparc/nscd-2.1.3-22.sparc.rpm
a611d30013f4f98576aebb58b906c6db  6.2/en/os/sparc/glibc-profile-2.1.3-22.sparc.rpm
a305bcbf7e6f273c0c9759b622b04509  6.2/en/os/sparc/glibc-devel-2.1.3-22.sparc.rpm
74ae10e642a463b053ef531048410330  6.2/en/os/sparc/glibc-2.1.3-22.sparc.rpm
ef78f44366467486a0dac8794bc17ab9  6.1/en/os/SRPMS/glibc-2.1.3-22.src.rpm
e768b72385324280d62b271895261021  6.1/en/os/alpha/nscd-2.1.3-22.alpha.rpm
57040728348767ef4475ab82091a3db0  6.1/en/os/alpha/glibc-profile-2.1.3-22.alpha.rpm
e5a7cf85e50c599a51e7b9ee7d1bc78d  6.1/en/os/alpha/glibc-devel-2.1.3-22.alpha.rpm
c1edf134c6d5790ce74d7c4272ec8687  6.1/en/os/alpha/glibc-2.1.3-22.alpha.rpm
1de8f29192f62e1cc33f76d920e20a1a  6.1/en/os/sparcv9/glibc-2.1.3-22.sparcv9.rpm
966d69ca5182a97315e1f7bf5a5b7c30  6.1/en/os/sparc/nscd-2.1.3-22.sparc.rpm
a611d30013f4f98576aebb58b906c6db  6.1/en/os/sparc/glibc-profile-2.1.3-22.sparc.rpm
a305bcbf7e6f273c0c9759b622b04509  6.1/en/os/sparc/glibc-devel-2.1.3-22.sparc.rpm
74ae10e642a463b053ef531048410330  6.1/en/os/sparc/glibc-2.1.3-22.sparc.rpm
b860e2f939f4e6517f4672361d746b38  6.1/en/os/i386/nscd-2.1.3-22.i386.rpm
e9b9b581fa4eda1a9aa2a5de8b267889  6.1/en/os/i386/glibc-profile-2.1.3-22.i386.rpm
2a779a3f6c3b87059cf40686f55dc2f6  6.1/en/os/i386/glibc-devel-2.1.3-22.i386.rpm
b841df797bf42585476f30b1ba489e30  6.1/en/os/i386/glibc-2.1.3-22.i386.rpm
ef78f44366467486a0dac8794bc17ab9  6.0/en/os/SRPMS/glibc-2.1.3-22.src.rpm
1de8f29192f62e1cc33f76d920e20a1a  6.0/en/os/sparcv9/glibc-2.1.3-22.sparcv9.rpm
966d69ca5182a97315e1f7bf5a5b7c30  6.0/en/os/sparc/nscd-2.1.3-22.sparc.rpm
a611d30013f4f98576aebb58b906c6db  6.0/en/os/sparc/glibc-profile-2.1.3-22.sparc.rpm
a305bcbf7e6f273c0c9759b622b04509  6.0/en/os/sparc/glibc-devel-2.1.3-22.sparc.rpm
74ae10e642a463b053ef531048410330  6.0/en/os/sparc/glibc-2.1.3-22.sparc.rpm
b860e2f939f4e6517f4672361d746b38  6.0/en/os/i386/nscd-2.1.3-22.i386.rpm
e9b9b581fa4eda1a9aa2a5de8b267889  6.0/en/os/i386/glibc-profile-2.1.3-22.i386.rpm
2a779a3f6c3b87059cf40686f55dc2f6  6.0/en/os/i386/glibc-devel-2.1.3-22.i386.rpm
b841df797bf42585476f30b1ba489e30  6.0/en/os/i386/glibc-2.1.3-22.i386.rpm
e768b72385324280d62b271895261021  6.0/en/os/alpha/nscd-2.1.3-22.alpha.rpm
57040728348767ef4475ab82091a3db0  6.0/en/os/alpha/glibc-profile-2.1.3-22.alpha.rpm
e5a7cf85e50c599a51e7b9ee7d1bc78d  6.0/en/os/alpha/glibc-devel-2.1.3-22.alpha.rpm
c1edf134c6d5790ce74d7c4272ec8687  6.0/en/os/alpha/glibc-2.1.3-22.alpha.rpm

These packages are GPG signed by Red Hat, Inc. for security. Our key is available at:
http://www.redhat.com/about/contact.html

You can verify each package with the following command: rpm --checksig filename

If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command: rpm --checksig --nogpg filename

Note that you need RPM >= 3.0 to check GnuPG keys.

8. References: