Beginning more than a decade ago, one of the largest security companies in the world, Moscow-based Kaspersky Lab, tried to damage rivals in the marketplace by tricking their antivirus software programs into classifying benign files as malicious, according to two former employees. They said the secret campaign targeted Microsoft Corp, AVG Technologies NV, Avast Software and other rivals, fooling some of them into deleting or disabling important files on their customers' PCs. Some of the attacks were ordered by Kaspersky Lab's co-founder, Eugene Kaspersky, in part to retaliate against smaller rivals that he felt were aping his software instead of developing their own technology, they said.

Kaspersky denies this claim - not that you would expect them to come out and say that they purposefully targeted other vendors with false reports - but the end result was that the open channels used to share malware information among vendors, which were based on trust, are now broken. The two former Kaspersky employees said that these attacks went on for more than 10 years with a peak between 2009 and 2013.

Well, I find it hard to trust any proprietary software these days (look at Windows 10). Obviously open source isn't perfect but the fact the source can be vetted by anyone makes me feel a little better about using it.