On Wed, May 14, 2008 at 12:00:15PM -0400, Sean Dague wrote: > Yesterday Debian issued a security advisory regarding their ssh package. > The key generator for openssl keys (affecting ssh, vpns, and certs) has > been non random since 2006 (more details here: > http://it.slashdot.org/it/08/05/13/1533212.shtml) > > If you are running any Ubuntu or Debian systems, make sure you upgrade > packages (the fixes hit the package repositories yesterday afternoon) > otherwise ssh is pretty much just telnet. Ubuntu will regenerate your > host keys for you, and give you other appropriate warnings, things are > more manual on the Debian front (I experienced it first hand on both > systems yesterday.)
This will also affect SSL keys - any self-signed certs and any commercially-signed certs are probably not very secure (the keys are definitely compromised, the cert data is merely questionable.) Any certs used for imaps, ssl-ftp, etc are also suspect. Additionally, this affects anyone with multi-user systems. If *any* of your users use ssh rsa/dsa keys instead of interactive-password to connect, and generated their user keys on a weakened system, then their logins on your system are now compromised. Ubuntu is working on a blacklist system to help with this, other distros will need to either adopt this or you'll have to scan your users authorized_keys files. This also affects YOUR ssh user keys. If you use ubuntu/debian on a local system and generated a ssh user key, you'll have to generate a new one, and *revoke the old one from all systems you ever copied it to* or your logins are now vulnerable. Yeah, this is a *huge* deal. I expect we'll keep seeing fallout from this one as time goes on. For those who are curious, the base of the problem is that someone decided that since valgrind threw a warning, they'd comment out most of the entropy generation magic in openssl. The end result of this is that basically the only entropy value used to generate your keys is the PID of the process calling it. Guess what happens really early in boot on a new system? SSH key generation. This means the PID seed is usually < 200. This makes it even *worse* than has been previously discussed. -m -- Mike Kershaw/Dragorn <[EMAIL PROTECTED]> GPG Fingerprint: 3546 89DF 3C9D ED80 3381 A661 D7B2 8822 738B BDB1 Know the rules other people live by. Know them well. Know them in the same way terrorists know about cars: so that you know where to put the bomb.
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