Summary Rack::CommonLogger can be exploited by crafting input that includes newline characters to manipulate log entries. The supplied proof-of-concept demonstrates injecting malicious content into logs. Details When a user provides the authorization credentials via Rack::Auth::Basic, if success, the username will be put in env['REMOTE_USER'] and later be used by Rack::CommonLogger for logging purposes. The issue occurs when a server intentionally or unintentionally allows a user creation with the username contain CRLF and white space characters, or the server just want to log every login attempts. If an attacker enters a username with CRLF character, the logger will log the malicious username with CRLF characters into the logfile. Impact Attackers can break log formats or insert fraudulent entries, potentially obscuring real activity or injecting malicious data into log files.
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=fe444acec441e7b597c0677c4c33b6b2e8cdd46c commit fe444acec441e7b597c0677c4c33b6b2e8cdd46c Author: Hans de Graaff <graaff@gentoo.org> AuthorDate: 2025-02-12 06:32:23 +0000 Commit: Hans de Graaff <graaff@gentoo.org> CommitDate: 2025-02-12 06:33:36 +0000 dev-ruby/rack: add 2.2.11, 3.0.12, 3.1.10 Bug: https://bugs.gentoo.org/949642 Signed-off-by: Hans de Graaff <graaff@gentoo.org> dev-ruby/rack/Manifest | 3 +++ dev-ruby/rack/rack-2.2.11.ebuild | 57 ++++++++++++++++++++++++++++++++++++++++ dev-ruby/rack/rack-3.0.12.ebuild | 45 +++++++++++++++++++++++++++++++ dev-ruby/rack/rack-3.1.10.ebuild | 49 ++++++++++++++++++++++++++++++++++ 4 files changed, 154 insertions(+)
