Hashes aren't the only thing that judge a file. Virus scanners today look for specific portions of files that look like malicious code, either by directly match

Hashes aren't the only thing that judge a file. Virus scanners today look for specific portions of files that look like malicious code, either by directly matching it or by tracing the code. Apparently some virus scanners traced too far into other parts of the executable's code, into the legitimate portions that are found as system components on computers today. It's a neat attack.