What is it?
http://en.wikipedia.org/wiki/CRIME_%28security_exploit%29
How to check?
echo -n | openssl s_client -connect localhost:443 | grep -E "(Compression|Expansion).*"
If those are on, you are busted.
What to do?
echo "export OPENSSL_NO_DEFAULT_ZLIB=yes" >> /etc/sysconfig/apache2
rcapache2 restart
grep --color -a OPENSSL_NO_DEFAULT_ZLIB /proc/`pgrep httpd | tail -1`/environ
echo -n | openssl s_client -connect localhost:443 | grep -E "(Compression|Expansion).*"