Cato Networks says extensions are being used to serve up unwanted adds, steal data, and divert users to malicious sites. The extensions were not being flagged as malicious by endpoint protection tools and threat intelligence systems. The theft of personal and corporate data is a real threat for organizations, the security vendor says. It’s hard to say what proportion of the overall Chrome extensions currently available are malicious, he says. Google has implemented multiple measures to vet the security of extensions uploaded to its Chrome Web Store, including blocking extensions from outside of official stores.