Fxsmsp Threat Group, an elite Russian hacking collective, is selling source code of three major anti-virus companies after infiltrating their networks. 

The price tag is $300,000 for the software source code and internal files. Source code flaws can be exploited and rendered useless, turned into malware or used for espionage. 

This group is well known for selling sensitive information from high-profile, corporations storing government or sensitive data.