The source code for one of Kaspersky's security suite products has been leaked online. You can download it from torrent and file hosting. websites for free.
It is reported that these sources were stolen from Kaspersky Lab in 2008 and the last changes made to them date from December 2007. The Kaspersky source code that recently made its way onto public websites was leaked by a former employee of the antivirus vendor, who is already serving a prison sentence for intellectual property theft. The former worker was subsequently arrested and sentenced to three years in jail, to be followed by another three of supervised release.
The code is written in C++ and Delphi and covers the anti-virus engine, as well as the anti-phishing, anti-dialer, anti-spam, parental control, and other modules. Kaspersky stressed the security of its current products was not at risk because they only contained small parts of the leaked code which didn't concern protection functions.
We don't know yet to what version of Kaspersky's security suite the sources actually correspond to, but 8.0 is the most likely candidate at this point.