This afternoon I received spams from fellow colleagues at work from their gmail account. Emails went to both my personal gmail account and to my work accounts. It looks like the emails are in the sent items, which is rather worrying as it means the spammer sent mail from the account rather than forging the headers to make it look like it came from the account. I know for a fact that the password was secure on at least one of the accounts so a weak password is not the culprit. A quick (ironic) google search shows that several people are twittering this in the past couple of hours (mine came in at 3.43pm (and I had another at 7.30pm).
Google’s standard answer is to change your password, which doesn’t really help when there is obviously a back door that is letting people into the account in the first place. The solutions provided are as follows:

If your account has been compromised/hacked/stolen you will need to check at least all of the following things:

Account Security:
Settings -> Accounts and Import -> Google Account Settings -> Change Password [pick a new secure password]
Settings -> Accounts and Import -> Google Account Settings -> Change Password Recovery Options [verify secret question, SMS and secondary e-mail address]

Potential Spam:
Settings -> General -> Signature [make sure nothing as been added]
Settings -> General -> Vacation Responder [make sure it’s disabled and empty]

E-mail Theft
Settings -> Accounts and Import -> Send Mail As [make sure it is using your correct e-mail address]
Settings -> Filters [no filters that forward or delete e-mail]
Settings -> Forwarding and POP/IMAP -> Forwarding [disabled or correct address]
Settings -> Forwarding and POP/IMAP -> POP Download [disabled]
Settings -> Forwarding and POP/IMAP -> IMAP Access [disabled]

Additional Information
Keeping account secure: https://mail.google.com/support/bin/answer.py?hl=en&answer=46526
Protecting your account:  https://mail.google.com/support/bin/answer.py?hl=en&answer=29407
If your account is compromised:  http://mail.google.com/support/bin/answer.py?hl=en&answer=50270

Ciao is also reporting similar issues today.

It would be interesting to see if any of the compromised accounts were on the Google Apps servers as this probably has greater repercussions for Google’s business model as people will trust Google even less. It will certainly raise questions at work on Monday as to whether we would recommend moving some clients to Google Apps. Even if you haven’t been hacked (check your sent items, filters and your frequent contacts for spam messages) I would still highly recommend you change your password NOW and ensure it is a complicated, non-dictionary based one.