GHSA-r74q-gxcg-73hx Improper Input Validation in simple_form

• RubyGems simple_form: < 5.0.0 → fixed in 5.0.0

Incorrect Access Control in `file_method?` in `lib/simple_form/form_builder.rb`; a user-supplied string is invoked as a method call Impact For pages that build a form using user input, it is possible for an attacker to manipulate the input and send any method present in the form object. For example: ```erb ... ``` The string provided in the variable `@user_supplied_string` would be invoked as a method call inside the `@user` object (unless the string contains any of the following: `password`, `time_zone`, `country`, `email`, `phone` and `url`). By manipulation that input, an attacker could do any of the following: • Code execution (call actions like `#destroy`) • Denial of Service (by executing a computation intensive method) • Information Disclosure (check the presence of methods, leak user information) Patches The problem was fixed in version `5.0`. Although it's a major version, there should be no issues with upgrading for `4.x`. The reason it was released in a major version is that the configuration `SimpleForm.file_methods` was deprecated in order to fix the problem. Workarounds The issue only happens with pages that build forms based on user-provided input. If your application doesn't do that, you're not affected. A workaround is to explicitly pass which type you want for an input since the issue lies on Simple Form's automatically discovery of input types. This can be done using the `as` option, like the following: ```erb ``` References [TDB] For more information If you have any questions or comments about this advisory: • Open an issue in https://github.com/plataformatec/simple_form • Email us at [email protected]