Ever since Google disclosed in January that Internet intruders had stolen information from its computers, the exact nature and extent of the theft has been a closely guarded company secret. But a person with direct knowledge of the investigation now says that the losses included one of Google’s crown jewels, a password system that controls access by millions of users worldwide to almost all of the company’s Web services, including e-mail and business applications.

In Google’s case, the intruders seemed to have precise intelligence about the names of the Gaia software developers, and they first tried to access their work computers and then used a set of sophisticated techniques to gain access to the repositories where the source code for the program was stored.

They then transferred the stolen software to computers owned by Rackspace, a Texas company that offers Web-hosting services, which had no knowledge of the transaction. It is not known where the software was sent from there. The intruders had access to an internal Google corporate directory known as Moma, which holds information about the work activities of each Google employee, and they may have used it to find specific employees.

This fits with what I've seen of APT's MO. They consider valid user credentials to be their holy grail. Most of their efforts are focused on having a reliable source for valid credentials, which they them use to impersonate users for logging into webmail and using whatever means of remote access organizations provide to users.