Guys,
SPAM problem is not related to security issues.
With 1.4.1 release we closed the hole that could allow malicious users to hack into the database and to get any user role. We wrote about this while announcing Oxwall 1.4.1, so you should update as soon as possible.
Spam problem is different and is related to the fact that somebody wrote a script that registers users (just as regular ones) and posts blog posts with spam content. Currently there are 2 possible solutions for that:
1) Download and install free antispam plugin for the Oxwall Store.
2) Consider activating mandatory user approval mode to manually let people in.
If you know how to fight spam more effectively, we'd be grateful if you shared your ideas with us. We are ready to work on the solution.
As usual, SPAM is not related to security and is possible for all pieces software.
Thanks,
Emil