Came across the following article from another tech news reader:
DOM-based Extension Clickjacking: Your Password Manager Data at Risk | Marek Tóth
Looks like Enpass is one of the many password manager extensions affected:
Mitigation
Browser extension developers should focus on the following parts. The missing fix of one method leads to the extension remaining vulnerable.
Extension Element
• styles cannot be changed (MutationObserver)
• using "Closed Shadow-Root"
Parent Element
• BODY/HTML opacity detection
• using Popover API for extension should protect this method
Extension Overlay
• last DOM element detection (z-index conflict)
• popover elements listing - when the autofill menu is opened, check if any other "top layer" elements exist
→ if another element exists the autofill menu should close
→ or just don't show extension UI if exist "popover" element
• elementsFromPoint() can be used for partial overlay but cannot be used for popover elements (pointer-events:none are ignored)
→ The content script can temporarily remove pointer-events:none from all popover elements before filling in data, then check the "top layer" state using elementsFromPoint() and fill the data accordingly.
Doesn't exist simple protection.⚠️
Some platform-level support should be created - new browser API protection for this clickjacking technique.⚠️
The proposed solutions are still handled through javascript and conflicts may occur between exploit code and extension content script (extension white-box analysis can be made). The safest solution is to display a new popup window - but that will be very inconvenient for users. Alternatively, a context menu or a system dialog for autofill may then be displayed.
Consider addressing this issue ASAP Enpass team.