The http parser in Phusion Passenger 6.0.21 through 6.0.25 before 6.0.26 allows a denial of service during parsing of a request with an invalid HTTP method.

RubyGems passenger 4.0.0 betas 1 and 2 allows remote attackers to delete arbitrary files during the startup process.

An issue was discovered in switchGroup() in agent/ExecHelper/ExecHelperMain.cpp in Phusion Passenger before 5.3.2. The set of groups (gidset) is not set correctly, leaving it up to randomness (i.e., uninitialized memory) which supplementary groups are actually being set while lowering privileges.

A race condition in the nginx module in Phusion Passenger 3.x through 5.x before 5.3.2 allows local escalation of privileges when a non-standard passengerinstanceregistrydir 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.

During the spawning of a malicious Passenger-managed application, SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows such applications to replace key files or directories in the spawning communication directory with symlinks. This then could result in arbitrary reads and writes, which in turn can result in information disclosure and privilege escalation.

An Insecure Permissions vulnerability in SpawningKit in Phusion Passenger 5.3.x before 5.3.2 causes information disclosure in the following situation: given a Passenger-spawned application process that reports that it listens on a certain Unix domain socket, if any of the parent directories of said socket are writable by a normal user that is not the application's user, then that non-application user can swap that directory with something else, resulting in traffic being redirected to a non-application user's process through an alternative Unix domain socket.

An Incorrect Access Control vulnerability in SpawningKit in Phusion Passenger 5.3.x before 5.3.2 allows a Passenger-managed malicious application, upon spawning a child process, to report an arbitrary different PID back to Passenger's process manager. If the malicious application then generates an error, it would cause Passenger's process manager to kill said reported arbitrary PID.

In agent/Core/SpawningKit/Spawner.h in Phusion Passenger 5.1.10 (fixed in Passenger Open Source 5.1.11 and Passenger Enterprise 5.1.10), 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.

In Phusion Passenger before 5.1.0, a known /tmp filename was used during passenger-install-nginx-module execution, which could allow local attackers to gain the privileges of the passenger user.

agent/Core/Controller/SendRequest.cpp in Phusion Passenger before 4.0.60 and 5.0.x before 5.0.22, when used in Apache integration mode or in standalone mode without a filtering proxy, allows remote attackers to spoof headers passed to applications by using an (underscore) character instead of a - (dash) character in an HTTP header, as demonstrated by an XUser header.

Phusion Passenger 4.0.37 allows local users to write to certain files and directories via a symlink attack on (1) controlprocess.pid or a (2) generation- file. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-1831.

An upstream commit [1] to the Passenger rubygem indicated that versions 4.0.5 and later are affected by a temporary file flaw described as follows:

" Phusion Passenger creates a "server instance directory" in /tmp during startup, which is a temporary directory that Phusion Passenger uses to store working files. This directory is deleted after Phusion Passenger exits. For various technical reasons, this directory must have a semi-predictable filename. If a local attacker can predict this filename, and precreates a symlink with the same filename that points to an arbitrary directory with mode 755, owner root and group root, then the attacker will succeed in making Phusion Passenger write files and create subdirectories inside that target directory. The following files/subdirectories are created:

controlprocess.pid generation-X, where X is a number.

If you happen to have a file inside the target directory called controlprocess.pid, then that file's contents are overwritten.

These files and directories are deleted during Phusion Passenger exit. The target directory itself is not deleted, nor are any other contents inside the target directory, although the symlink is. "

It is fixed in upstream version 4.0.33.

[1] https://github.com/phusion/passenger/commit/34b1087870c2

ext/common/ServerInstanceDir.h in Phusion Passenger gem before 4.0.6 for Ruby allows local users to gain privileges or possibly change the ownership of arbitrary directories via a symlink attack on a directory with a predictable name in /tmp/.

Michael Scherer reported that the passenger ruby gem, when used in standalone mode, does not use temporary files in a secure manner. In the lib/phusionpassenger/standalone/main.rb's createnginxcontroller function, passenger creates an nginx configuration file insecurely and starts nginx with that configuration file:

@tempdir = "/tmp/passenger-standalone.#{$$}" @configfilename = "#{@tempdir}/config"

If a local attacker were able to create a temporary directory that passenger uses and supply a custom nginx configuration file they could start an nginx instance with their own configuration file. This could result in a denial of service condition for a legitimate service or, if passenger were executed as root (in order to have nginx listen on port 80, for instance), this could lead to a local root compromise.

Michael Scherer reported that the passenger ruby gem, when used in standalone mode, does not use temporary files in a secure manner. In the lib/phusionpassenger/standalone/main.rb's createnginxcontroller function, passenger creates an nginx configuration file insecurely and starts nginx with that configuration file:

@tempdir = "/tmp/passenger-standalone.#{$$}" @configfilename = "#{@tempdir}/config"

If a local attacker were able to create a temporary directory that passenger uses and supply a custom nginx configuration file they could start an nginx instance with their own configuration file. This could result in a denial of service condition for a legitimate service or, if passenger were executed as root (in order to have nginx listen on port 80, for instance), this could lead to a local root compromise.