I got 5 on it
Earlier today, a virus signature from the [over 25 years old] virus “DOS/STONED” was uploaded into the Bitcoin blockchain, which allows small snippets of text to accompany user transactions with bitcoin. Since this is only the virus signature and not the virus itself, there apparently is no danger to users in any way. However, MSE recognizes the signature for the virus and continuously reports it as a threat, and every time it deletes the file, the bitcoin client will simply re-download the missing blockchain.
Whoever did this, I commend their sense of humour.