Hijacking Apps Using Archive Utility
Talal Haj Bakry and Tommy Mysk (Mastodon):
Until macOS 26.4, Archive Utility had nearly unrestricted filesystem access. Combined with a drag-and-drop sandbox quirk, this let an attacker bypass App Sandbox data containers, Transparency, Consent, and Control (TCC) protections, and hijack third-party apps — all without special permissions or elevated privileges.
[…]
Here’s one interesting aspect of the macOS app sandbox: dragging and dropping a file or folder onto an application grants it unrestricted access to the dropped item. This is by design. Without it, apps couldn’t access files dragged from protected locations like
~/Desktopor~/Documents, and drag and drop wouldn’t work in sandboxed apps at all.[…]
Knowing about the drag-and-drop loophole, an attacker can try to convince a user to drag and drop Archive Utility’s preferences file into Terminal, which lets them rewrite Archive Utility’s output folder. From there, copying a file out of an app data container is a two-step move: compress the target file inside a protected area, then extract the archive into a folder the attacker controls.
[…]
Code signing should have prevented this kind of tampering with the application bundle, but for some reason macOS didn’t complain. We would like to investigate this further.
Previously:
- Privacy & Security Settings Don’t Show Intent-Based Access
- macOS 26.4 Paste Protection
- macOS 26.4
- TCC and Gatekeeper Bypasses
- Persistent File Access via com.apple.macl Xattr
