CVE-2020-15146: Remote Code Execution in OptionsParser while using request parameters inside expression language

Description Impact Request parameters injected inside an expression evaluated by symfony/expression-language package haven’t been sanitized properly. This allows the attacker to access any public service by manipulating that request parameter, allowing for Remote Code Execution. The vulnerable versions include: <=1.3.13 || >=1.4.0 <=1.4.6 || >=1.5.0 <=1.5.1 || >=1.6.0 <=1.6.3. Example sylius_grid: grids: foo: fields: bar: options: baz: “expr:service(‘sylius.repository.product’).find($id)” In this case, $id can be prepared in a way that calls other services. If you visit /route?id=“~service(‘doctrine’).getManager().getConnection().executeQuery(“DELETE * FROM TABLE”)~”, it will result in a following expression expr:service(‘repository’).find(“”~service(‘doctrine’).getManager().getConnection().executeQuery(“DELETE * FROM TABLE”)~“”), which will execute a query on the currently connected database. To find a vulnerability in your application, look for any routing definition that uses request parameters inside expression language. Patches This issue has been patched for versions 1.3.14, 1.4.7, 1.5.2 and 1.6.4. Versions prior to 1.3 were not patched. Workarounds The fix requires adding addslashes in OptionsParser::parseOptionExpression to sanitize user input before evaluating it using the expression language. - return is_string($variable) ? sprintf(‘“%s”’, $variable) : $variable; + return is_string($variable) ? sprintf(‘“%s”’, addslashes($variable)) : $variable; Acknowledgements This security issue has been reported by Craig Blanchette (@isometriks), thanks a lot! For more information If you have any questions or comments about this advisory: Email us at [email protected]