Millions of users on some of the most popular software in the world will have to wonder who holds their data, with Adobe revealing it was hacked and had masses of information stolen.

The source code for Adobe Acrobat, Cold Fusion and other products creates a nearly unprecedented threat, given how broadly-installed these programs are.

Adobe Chief Security Officer Brad Arkin says personal information was stolen.

“Our investigation currently indicates that the attackers accessed Adobe customer IDs and encrypted passwords on our systems. We also believe the attackers removed from our systems certain information relating to 2.9 million Adobe customers, including customer names, encrypted credit or debit card numbers, expiration dates, and other information relating to customer orders. At this time, we do not believe the attackers removed decrypted credit or debit card numbers from our systems,” Arkin said in a blog.

Brian Krebs from Hold Security, the company credited with discovering the breach expanded on the attack.

“Over 40 Gigabytes in encrypted archives have been discovered on a hackers’ server that appear to contain source code of such products as Adobe Acrobat Reader, Adobe Acrobat Publisher, and the Adobe ColdFusion line of products. It appears that the breach of Adobe’s data occurred in early August of this year but it is possible that the breach was ongoing earlier. While it is unclear at this time how the hackers obtained the source code and whether they analysed or used it for malicious purposes, it appears that the data was taken and viewed by unauthorized individuals.”

The big risk highlighted by most security experts is that with the source code, it should be much easier for somebody to design an exploit for the software with the original code at hand, rather than through extensive 'black-box' testing.

The potential to create highly-customised attacks on Adobe products will be less than reassuring for the millions upon millions of users with Acrobat Reader installed on their computers or phones.

Adobe says at this point it is unaware of any exploits targeting its products.

The announcement post from Adobe’s Chief of Security is available here.