CVE-2021-30657 — Malicious applications may bypass Gatekeeper checks

A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina. A malicious application may bypass Gatekeeper checks. Apple is aware of a report that this issue may have been actively exploited…

Recent assessments:

space-r7 at April 28, 2021 8:19pm UTC reported:

Rating this vulnerability as high since it bypasses all of the checks that MacOS performs on downloaded files. It was reportedly introduced in MacOS version 10.15, and the fix is in version 11.3. This vulnerability has also been reported as being exploited in the wild.

An unsigned, unnotarized binary downloaded from the Internet is typically blocked from execution; however a script-based app with no Info.plist file bypasses those checks. To read about how that exactly happens, see the objective-see blog post here. This does require user interaction for success, but all it takes is a download and a double click. Additionally, an exploit is quite trivial to make, as all it really needs is a valid app without the Info.plist file bundled with it. As always, install your updates.

Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 4