The recommended Apache/Nginx virtual host configuration for eZ Platform includes a rewrite rule for blocking access to executable files in the var directory. This rule does not work when using eZ Platform Cloud (i.e. running eZ Platform on the Platform.sh cloud service).
The consequence of this is that in such a setup, those executable files may be downloadable. They will not be executable, unless you have specifically configured platform.sh to allow that (which you really should not do). The severity of the download access is limited, but it's better if the platform.sh cloud setup works the same way as regular eZ Platform does. All platform.sh setups are affected.
The fix adds a rule to the .platform.app.yaml configuration file, with the same effect as the rewrite rule already mentioned. After applying the fix, any attempt to access such files will fail with Access Denied. This security update is distributed via Composer as ezsystems/ezplatform 18.104.22.168, and 22.214.171.124, and 2.5.4. This is the commit: https://github.com/ezsystems/ezplatform/commit/773dddc0d8fe4fda34d2153a401eeaa6cc30b1ff
This issue was reported to us by Serhey Dolgushev from Contextual Code: https://www.contextualcode.com/
We are very grateful for his research, and responsible disclosure to us.