Attachments in 1krBlocker never open by themselves. They appear as a card marked Isolated. The Attachment group on the Why? screen says how risky a file type is:
- "Has an attachment that may be unsafe to open (…)": PDFs, Office documents and unknown types can carry harmful content or links. You can open them in another app after a warning, if you expected the file from this sender.
- "Has an attachment that can harm your phone (…)": app installers and similar files that can install apps or run code. The app shows "This file type can harm your phone. It will not be opened." and won't open it at all.
Photos are shown as a preview inside 1krBlocker (Tap to preview).
If you really need a dangerous file (for example an installer a friend sent on purpose), you can still use Export…; 1krBlocker warns you first because the copy is outside its protection. Never install an app that arrived by text message, even from someone you know: their phone may be infected.
Attachments never leave your phone for checking.