Hackers broke into the internal computer network of Adobe Systems and stole information on 2.9 million customers, as well as source code for several of the company's products.

Adobe's security team discovered "sophisticated attacks" on the company's network "very recently," Brad Arkin, Adobe's chief security officer, said Thursday in a blog post announcing the incident.

So far, Adobe's investigation has revealed that attackers managed to access Adobe customer IDs and encrypted passwords, as well as obtain information on 2.9 million customers, including names, encrypted credit or debit card numbers with their expiration dates, and other customer order details.

"At this time, we do not believe the attackers removed decrypted credit or debit card numbers from our systems," Arkin said.

"Our investigation to date indicates that the cyber attackers removed certain customer information between September 11 and September 17, 2013," an Adobe spokeswoman said via email. As far as the timeline for the source-code compromise is concerned, the investigation is ongoing, she said.

It's not clear if the same attackers are responsible for the compromise of customer information and accounts and the theft of source code.

Adobe is in the process of resetting the passwords of all affected Adobe ID accounts and notifying customers whose credit or debit card information was involved in the security breach. The company is offering U.S.-based customers a one-year complimentary membership in a credit monitoring service.

Adobe has alerted the banks processing customer payments and is working with external partners and law enforcement to address the incident.

Computerworld