7. Problem description:
INN versions 2.2 and earlier have a buffer overflow-related security
condition in the inews program.
inews is a program used to inject new postings into the news system. It is
used by many news reading programs and scripts. The default installation is
with inews setgid to the news group and world executable. It's possible that
exploiting the buffer overflow could give the attacker news group
privileges, which could possibly be extended to root access.
Note that this chain of elevation of privileges is theoretical rather than
actual; the ability of an attacker to do this indicates bugs in other
portions of INN. However, given the degree to which INN trusts the news user
and news group, it's not unlikely that such bugs exist.
No case of this being exploited has been shown yet.
If you run a news server with no local readers (i.e. all your clients are
remote) then you can remove the setgid-bit on inews.
chmod 0550 inews
The rnews program, used to feed news via uucp, is setuid to the
uucp user. No buffer overflow problems have been found in rnews,
but if you don't run uucp on your machine, then we recommend
disabling the setuid bit on rnews:
chown news rnews
chgrp news rnews
chmod 0550 rnews
Red Hat Linux releases 4.2 and 5.2 shipped with a version of INN that is no
longer being maintained. We have back-ported the latest 2.2.1 INN version to
those older Red Hat Linux releases. The new package will not be an exact
drop in for the older packages, so it is advisable to save you config files
first before starting the migration to the new code base. Alternatively you
can implement some of the solutions described above if you do not want to
update to a new version of INN.
Also, on Red Hat Linux 4.2 inn will require a new package named cleanfeed
that is also shipped as part of this advisory.
Thanks go to the members of the BUGTRAQ mailing list for bringing this issue
to our attention.
8. Solution:
For each RPM for your particular architecture, run:
rpm -Uvh filename
where filename is the name of the RPM.
Then, restart innd:
/etc/rc.d/init.d/innd restart
9. Verification:
MD5 sum Package Name
-------------------------------------------------------------------------
71dfbbfaddc1596f1e6357562691e3e5 i386/inn-2.2.1-1.i386.rpm
2201608f6d72d96041998349b401061c i386/inn-devel-2.2.1-1.i386.rpm
5dad0596a6db0beace1441484229cb35 alpha/inn-2.2.1-1.alpha.rpm
fbc0789c46f953dffdd3503551f2a293 alpha/inn-devel-2.2.1-1.alpha.rpm
b8d18a074b1e703e386a9b514e099653 sparc/inn-2.2.1-1.sparc.rpm
b539e8f684279b4e607d475d5225844d sparc/inn-devel-2.2.1-1.sparc.rpm
7c58191dc271e462e59e97e58735e52f SRPMS/inn-2.2.1-1.src.rpm
These packages are also PGP 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 --nopgp filename
10. References: