They're still actively used to apply the Mark of the Web to indicate a file has been downloaded from an untrusted zone and should be handled with caution. I believe macOS also applies similar metadata.
There are a few other places where they also show up, but the MotW is the most prevalent one I've found. Most antivirus programs will warn you for unusual alternate data streams regardless of what they contain.
alt Hacker News
They're still actively used to apply the Mark of the Web to indicate a file has been downloaded from an untrusted zone and should be handled with caution. I believe macOS also applies similar metadata.
There are a few other places where they also show up, but the MotW is the most prevalent one I've found. Most antivirus programs will warn you for unusual alternate data streams regardless of what they contain.