CVE-2019-16782

There's a possible information leak / session hijack vulnerability in Rack. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session.

The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.

Impact

The session id stored in a cookie is the same id that is used when querying the backing session storage engine. Most storage mechanisms (for example a database) use some sort of indexing in order to speed up the lookup of that id. By carefully timing requests and session lookup failures, an attacker may be able to perform a timing attack to determine an existing session id and hijack that session.

Releases

The 1.6.12 and 2.0.8 releases are available at the normal locations.

Workarounds

There are no known workarounds.

Patches

To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

• 1-6-session-timing-attack.patch - Patch for 1.6 series
• 2-0-session-timing-attack.patch - Patch for 2.6 series

Credits

Thanks Will Leinweber for reporting this!

There's a possible information leak / session hijack vulnerability in Rack (RubyGem rack). This vulnerability is patched in versions 1.6.12 and 2.0.8. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session. The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.

Updated ruby-rack packages fix security vulnerabilities:

There's a possible information leak / session hijack vulnerability in Rack(RubyGem rack). Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session. The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison (CVE-2019-16782).

If certain directories exist in a director that is managed by Rack::Directory, an attacker could, using this vulnerability, read the contents of files on the server that were outside of the root specified in the Rack::Directory initializer (CVE-2020-8161).

This update for rubygem-rack to version 2.0.8 fixes the following issues:

• CVE-2018-16471: Fixed a cross-site scripting (XSS) flaw via the scheme method on Rack::Request (bsc#1116600).
• CVE-2019-16782: Fixed a possible information leak and session hijack vulnerability (bsc#1159548).

This update was imported from the SUSE:SLE-15:Update update project.

These are all security issues fixed in the ruby2.7-rubygem-actioncable-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-actionmailer-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-actionpack-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-actionpack-6.0-6.0.4-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-actionview-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-activejob-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-activemodel-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-activerecord-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-activestorage-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-activesupport-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-rack-2.2.3-1.7 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-rack-2.0-2.0.9-1.10 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-rails-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby2.7-rubygem-railties-5.2-5.2.6-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.1-rubygem-actionpack-6.0-6.0.4.4-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.1-rubygem-rack-2.2.3.1-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.1-rubygem-rack-2.2-2.2.4-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.2-rubygem-rack-2.2-2.2.7-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.2-rubygem-rack-3.0.7-1.2 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.3-rubygem-rack-3.0.9.1-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.3-rubygem-rack-2.2-2.2.8.1-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.4-rubygem-rack-2.2-2.2.11-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby3.4-rubygem-rack-3.1.12-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby4.0-rubygem-rack-2.2-2.2.22-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the ruby4.0-rubygem-rack-3.1.18-1.3 package on the GA media of openSUSE Tumbleweed.

This update for rubygem-rack to version 2.0.8 fixes the following issues:

• CVE-2018-16471: Fixed a cross-site scripting (XSS) flaw via the scheme method on Rack::Request (bsc#1116600).
• CVE-2019-16782: Fixed a possible information leak and session hijack vulnerability (bsc#1159548).

This update for rubygem-rack to version 1.6.13 fixes the following issues:

• CVE-2020-8184: Fixed an issue where percent-encoded cookies could have been used to overwrite existing prefixed cookie names (bsc#1173351).
• CVE-2020-8161: Fixed a directory traversal (bsc#1172037).
• CVE-2019-16782: Fixed an information leak / session hijack vulnerability (bsc#1159548).

This update for rubygem-actionpack-4_2 fixes the following issues:

• CVE-2019-16782: Possible Information Leak / Session Hijack Vulnerability in Rack (bsc#1159548)

It was discovered that Rack insecurely handled session ids. An unauthenticated remote attacker could possibly use this issue to perform a timing attack and hijack sessions. (CVE-2019-16782)

It was discovered that Rack was incorrectly handling cookies during parsing, not validating them or performing the necessary integrity checks. An attacker could possibly use this issue to overwrite existing cookie data and gain control over a remote system's behaviour. This issue only affected Ubuntu 14.04 ESM. (CVE-2020-8184)

It was discovered that Rack was not properly parsing data when processing multipart POST requests. If a user or automated system were tricked into sending a specially crafted multipart POST request to an application using Rack, a remote attacker could possibly use this issue to cause a denial of service. This issue was only fixed in Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. (CVE-2022-30122)

It was discovered that Rack was not properly escaping untrusted data when performing logging operations, which could cause shell escaped sequences to be written to a terminal. If a user or automated system were tricked into sending a specially crafted request to an application using Rack, a remote attacker could possibly use this issue to execute arbitrary code in the machine running the application. This issue was only fixed in Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. (CVE-2022-30123)