Target's chief information officer has resigned as the retailer overhauls its information security practices in the wake of a giant customer data breach, the company said Wednesday. Beth Jacob, who was in charge of Target's computer systems since 2008, has resigned, a company spokeswoman said, in the first major executive departure since the company announced the hacking incident in December. Target will launch an external search for an interim CIO as well as for a chief information security officer whose role will be "elevated" in the wake of the data breach, chief executive Gregg Steinhafel said in a statement. The company also plans to undertake an external search for a chief compliance officer. Target has been under scrutiny since disclosing in December that a data breach had resulted in the theft of credit-card data for some 40 million customers. In January, however, it said its own investigation had revealed that hackers also stole a second batch of data that included names, mailing addresses, phone numbers or email addresses for up to 70 million people. The company is cooperating with investigations by the Justice Department and Secret Service. Security researchers have said that the theft of data for up to 110 million people is probably linked to a broader global network of cybercrime. "While we are still in the process of an ongoing investigation, we recognize that the information security environment is evolving rapidly," said Steinhafel said. "To ensure that Target is well positioned following the data breach we suffered last year, we are undertaking an overhaul of our information security and compliance structure and practices at Target."