Описание
Rack::Static prefix matching can expose unintended files under the static root
Summary
Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql".
As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure.
Details
Rack::Static#route_file performs static-route matching using logic equivalent to:
This checks only whether the request path starts with the configured prefix string. It does not require a path segment boundary after the prefix.
For example, with:
the following path is matched as intended:
but these paths are also matched:
If such files exist under the configured static root, Rack forwards the request to the file server and serves them as static content.
This means a configuration intended to expose only directory trees such as /css/... and /js/... may also expose sibling files whose names begin with those same strings.
Impact
An attacker can request files under the configured static root whose names share a configured URL prefix and obtain their contents.
In affected deployments, this may expose configuration files, secrets, backups, environment files, or other unintended static content located under the same root directory.
Mitigation
- Update to a patched version of Rack that enforces a path boundary when matching configured static URL prefixes.
- Match only paths that are either exactly equal to the configured prefix or begin with
prefix + "/". - Avoid placing sensitive files under the
Rack::Staticroot directory. - Prefer static URL mappings that cannot overlap with sensitive filenames.
Пакеты
rack
< 2.2.23
2.2.23
rack
>= 3.0.0.beta1, < 3.1.21
3.1.21
rack
>= 3.2.0, < 3.2.6
3.2.6
Связанные уязвимости
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, ...
Уязвимость модульного интерфейса веб-сервера Rack языка программирования Ruby, позволяющая нарушителю получить несанкционированный доступ к защищаемой информации