Microsoft cloud services are scanning for malware by peeking inside users’ zip files, even when they’re protected by a password, several users reported on Mastodon on Monday.
https://infosec.exchange/@threatresearch/110373860063222707
“If you mail yourself something and type something like 'ZIP password is Soph0s', ZIP up EICAR and ZIP password it with Soph0s, it'll find (the) password, extract and find (and feed MS detection),”
One other thing readers should remember: password-protected zip files provide minimal assurance that content inside the archives can’t be read. As Beaumont noted, ZipCrypto, the default means for encrypting zip files in Windows, is trivial to override. A more dependable way is to use an AES-256 encryptor built into many archive programs when creating 7z files.