JobStreet and other job sites have their own "Anti-Fraud" measures. However it's not easy to have 100% fraud-free website as some of these bad guys are very smart and smooth.

Anyway the rule of thumb is always to "Google" about a company if it is not well known. The rule of thumb is "if the offer is too good to be true, then it might not be true" and never pay some processing fees to get a job.