Package Instance

Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)
A race condition in the nginx module in Phusion Passenger allows local escalation of privileges when a non-standard `passenger_instance_registry_dir` with insufficiently strict permissions is configured. Replacing a file with a symlink after the file was created, but before it was chowned, leads to the target of the link being chowned via the path. Targeting sensitive files such as root's crontab file allows privilege escalation.

Information Exposure
If Passenger is running as root, it is possible to list the contents of arbitrary files on a system by symlinking a file named REVISION from the application root folder to a file of choice and querying `passenger-status --show=xml`.

Utils.cpp Temporary Directory Creation Symlink Local Privilege Escalation
This package contains a flaw as the program creates temporary directories insecurely. It is possible for a local attacker to use a symlink attack against the Utils.cpp file to allow the attacker to gain elevated privileges.

Header overwriting
It is possible in some cases, for clients to overwrite headers set by the server, resulting in a medium level security issue. Passenger 5 uses an SCGI-inspired format to pass headers to Ruby/Python applications, while Passenger 4 uses an SCGI-inspired format to pass headers to all applications. This implies a conversion to UPPER_CASE_WITH_UNDERSCORES whereby the difference between characters like '-' and '_' is lost. See "Affected use-cases" in provided link to establish wether one particular application is affected.

Instance Directory Creation Symlink Arbitrary File Overwrite
Passenger Gem for Ruby contains a flaw as the program creates the server instance directory insecurely. It is possible for a local attacker to use a symlink attack against the directory to cause the program to unexpectedly overwrite an arbitrary file.

Information Exposure
If Passenger is running as root, it is possible to list the contents of arbitrary files on a system by symlinking a file named REVISION from the application root folder to a file of choice and querying `passenger-status --show=xml`.