Kurt Seifried Security Advisory 002 (KSSA-002)
Created by Kurt Seifried, firstname.lastname@example.org
Red Hat 7.2 GnuPG signed RPM verification fails on distribution files
Oct 23, 2001
History of advisory:
Oct 23, 2001 While downloading Red Hat 7.2 Kurt Seifried noticed various packages were not GnuPG signed.
Kurt Seifried email@example.com
Red Hat 7.2 distribution files on popular ftp sites such as ftp.ibiblio.org and mirrors.hpcf.upr.edu are not signed. It is unlikely that this is an attack as the number of sites involved makes it likely someone would have noticed and notified the community. Either Red Hat did not sign these packages, or someone subverted the distribution process before the files got to various sites. For Red Hat 7.1 please note that all files were correctly signed with the Red Hat GnuPG security key.
An attacker can create RPM's that will not appear any different from the real ones, as they do not need to be signed. Finding the MD5 sums of the files in trusted locations is very difficult (I cannot find any lists).
Red Hat has released Red Hat 7.2, a much anticipated release. Typically all the rpm distribution files are signed, making it very easy to verify their correctness. Since numerous packages are not signed it becomes trivial for an attacker to replace packages on a distribution site with no-one being able to easily verify that they have been subverted. An attacker would not even need to modify or add files to the package, instead they could add a preinstall, postinstall, preuninstall or postuninstall script that would be capable of compromising the system since these scripts run with root privileges. Packages include rpmdb-redhat and redhat-release.
Solutions and workarounds:
None available. Red Hat needs to sign the packages properly with GnuPG.
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Last updated 10/23/2001
Copyright Kurt Seifried 2001