As a computer expert, i know that even a half backed hacker could hide his track perfectly. So, if the russians (or chineses) hacked it then, the chances too find who did it are zero. Also, the russians (among the germans) are in the top of the hacking community.
For example, let’s say that i want to hack Microsoft.com, i won’t use my home or office IP, i will rent (using a stolen CC) or hack a second server (usually in a country that they don´t care about logs IP) and i will use this server to attack… another server. And with this third server, i finally hack Microsoft.com. Microsoft will only find that the third server is trying to access to their server.
For an example, some hackers groups are been actives and unidentified since REAGAN.
So far, they are show zero evidence. Just a (so called) expert said about it was the russians because the modus operandis. PEOPLE IS NOT SO NAIVE!