When Firefox 32 shipped this week, Mozilla also officially ended its support of 1024-bit certificate authority certificates in its trusted store.
While it still takes a considerable amount of resources to factor and crack a 1024-bit RSA key, important organizations such as NIST have been advising organizations to move to 2048-bit keys or higher going as far back as 2011. Microsoft announced a change to its certificate key length requirements shortly thereafter, yet others including Google, have been slow to follow suit.