Target Corp.’s chief information officer is the first casualty in the embarrassment of having its point of sale system hacked and the theft of millions of credit card numbers and personal data.

The Associated Press reported on Wednesday that Beth Jacob, who had overseen everything from Target’s Web site to its internal computer systems as chief information officer since 2008, has resigned.

The question is will she be the only person to be affected.

The retailer has said that entry to its systems was gained through an unnamed vendor. Since then there have been reports that a heating, ventilation and air conditioning (HVAC) company that was working on Target’s physical plant was the way in.

In a ComputerWorld U.S. report on the resignation an analyst wondered if there’d be repercussions against the company that assessed Target’s compliance with the Payment Card Industry (PCI) Data Security Standard, which retailers have to comply with.

Target hasn’t said anything about that. It hasn’t issued a full statement on exactly how the break-in was accomplished so others may take a hit. When that is revealed — and for security and legal reasons it will likely not be terribly detailed — we’ll learn whether Target was just unlucky, the victim of an incredibly imaginative hacker or whether the breach could have easily been prevented.

Meanwhile the company says it is accelerating its implementation of “smart card technology designed to dramatically reduce the threat of credit and debit card fraud among guests shopping in its stores.”