Google’s Internet Backbone AS15169, AS15169 & AS1680 (NV) are acting as intermediaries for malware distribution according to Google’s own Safe Browsing tool. The tool indicates that out of 542596 websites tested on the AS15169 network alone, 15606 websites served content that resulted in malicious software being downloaded and installed without user consent.

Here are the result of diagnostics on the networks mentioned above.

http://www.google.com/safebrowsing/diagnostic?site=AS:15169

http://www.google.com/safebrowsing/diagnostic?site=AS:1680

Surprisingly Google Code is a culprit as well.

“This network has hosted sites that have distributed malicious software in the past 90 days. We found 59 site(s), including, for example, googlecode.com has … infected 117 other site(s)”

Screenshot - Click to enlarge