Mac App Store November 25
Mac App Store November 18
Mac App Store November 12
The Mac App Store noticeably experienced some problems last night / early this morning with downloaded apps. Upon opening affected apps, the system would say that the app is ‘damaged’ and cannot be opened, just like the examples from Graham. It certainly seems scary at first glance.
The error message recommends reinstalling your apps individually. While this will fix the problem, it’s a pain to do and isn’t necessary at all: your apps are fine, but the error message makes the situation sound far worse than it is. To simply fix the problem, just reboot your Mac, running OS X Yosemite or El Capitan, and the problem will ‘magically’ go away.
The more interesting question is, why did this happen at all?
Mac App Store November 11
Mac App Store September 30
Patrick Wardle, director of research at security firm Synack, told arsTechnica that once Gatekeeper okays an approved app, it pays no more attention to what that app does. The approved app can then open malicious apps – which Gatekeeper doesn’t check.
Wardle has found a widely available binary that’s already signed by Apple. Once executed, the file runs a separate app located in the same folder as the first one […] His exploit works by renaming Binary A but otherwise making no other changes to it. [He then] swaps out the legitimate Binary B with a malicious one and bundles it in the same disk image under the same file name. Binary B needs no digital certificate to run, so it can install anything the attacker wants …