Target workers: We warned of security trouble before hack

Daniel Acker | Bloomberg | Getty Images

Target's own employees claim they raised their voices over security vulnerabilities months before hackers stole credit card and billing information belonging to as many as 70 million customers, according to an article in the Wall Street Journal.

At least one analyst within the company reportedly pushed for a review of the retailer's credit card payment terminals, not long after learning of new threats to those systems from industry and government reports.

At the time, Target was upgrading its payment systems in time for the busy and competitive holiday shopping season, the article said.

Hackers first broke into Target's system through a contractor that works with Target, not the payment terminals. According to sources cited in the article, hackers should not be able to access payment information through a contractor.

(Read more: Target-style databreach hits UK supermarket )

Target did not comment on the warnings by analysts, but the company told Congress last week that it has passed an audit for its payment systems, last September. The story also said the company spends quite a bit on security, and includes former federal agents among its cybersecurity staff.

To read the full story in the Wall Street Journal, click here.