also, defender is synchronous by default (e.g. nothing gets written until it gets scanned, and scanning parallelization is limited), and can only act asynchronously (aka write first, then queue check) on “trusted dev drives” (aka ReFS-based virtual vhdx partitions aimed at developers as a solution to horrible ntfs throughput, especially if defender is enabled)
Not just every file deleted, every file written to disk as well (downloaded, extracted from an archive, whatever).
It’s also how most AV software works, except Defender is slow AF.
I thought it checks every file closed
No, it scans file headers when you do read/write operations on disk. Every AV works this way, except, as I said, Defender is slow AF.
I can’t find talk I watched, but I found github issue it was based on.
Short version: Defender is triggered not on open, not on read or write, but on CloseHandle.
CloseHandle of what? Read/write operations?
Found! Even metadata chamge.
Huh. All that security, and yet there are still so many viruses capable of infecting windows.
Huh… all that immune system yet there are still so many viruses capable of infecting humans.
also, defender is synchronous by default (e.g. nothing gets written until it gets scanned, and scanning parallelization is limited), and can only act asynchronously (aka write first, then queue check) on “trusted dev drives” (aka ReFS-based virtual vhdx partitions aimed at developers as a solution to horrible ntfs throughput, especially if defender is enabled)