A civil servant leaked a secret and was punished for the crime of leaking secrets.

Literal

Civil-servant [subject-が] secret [object-を] leaked [then-て], secret-leaking-crime [as-として] was-punished.

公務員 means 'civil servant.' 秘密漏洩罪 (ひみつろうえいざい) is a legal compound: 'crime of leaking secrets.' ~として marks the charge: 'as the crime of X.' 罰せられた is the passive of 罰する ('to punish').