oss-sec mailing list archives

Re: libdbus hardening


From: Tomas Hoger <thoger () redhat com>
Date: Thu, 13 Sep 2012 18:18:17 +0200

On Tue, 10 Jul 2012 16:11:12 +0200 Sebastian Krahmer wrote:

If you compile your openssh '--with-ssl-engine' you have
an easy root exploit (given that ssh-keysign is mode 04755
such as on Debian) via OPENSSL_config().

Even though the above is not correct to the best of my knowledge (no
openssh version I checked would call OPENSSL_config(NULL) from
ssh-keysign, even when it's complied with --with-ssl-engine and
installed setuid root; even though other openssh command line tools do
end up calling OPENSSL_config(NULL)), this shows OpenSSL is not
unlikely to be used in a privileged application and hence may allow
privilege escalation via special OPENSSL_CONF or OPENSSL_ENGINES
environment variables.

OpenSSL also already protects access to certain environment variables
(there are OPENSSL_issetugid() calls before getenv()), it does not do
the same check for all variables it reads.  It seems that problem
deserves a CVE.

-- 
Tomas Hoger / Red Hat Security Response Team


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