On 11/6/26 00:35, Peter Gutmann wrote:
Jeffrey Walton <[email protected]> writes:
One general comment that does not fit well into most of the discussions around
sshole...
Another contributing factor, "sshd borrows bob's salt" and the derived
changes, was the quaint 1970s notion that no-one would ever be able to guess
that there exist account names like root, daemon, ldap, postfix, apache,
mysql, sshd, and rumpelstiltskin, so we'll add a kludge to make invalid
accounts take the same time as valid ones. Attackers don't even notice this
because they start with a pregenerated list of known and probable accounts,
but it does help to add vulnerabilities to the password-checking process as
this CVE shows.
Does it even entirely work? What if there is no salt to borrow?
Thinking about this, I think I see another information leak: does sshd
produce a "fake salt" or fail the authentication quickly, thus leaking
the fact that no accounts on the box have a valid password?
There was a time when a salt could be assumed to exist, but that was
before cloud VM images that have no console and therefore can be
network-login-with-SSH-key only...
-- Jacob
