Advisory Weakness Curation

actionpack allows bypass of database-query restrictions `actionpack/lib/action_dispatch/http/request.rb` in Ruby on Rails before 3.2.16 and 4.x before 4.0.2 does not properly consider differences in parameter handling between the Active Record component and the JSON implementation, which allows remote attackers to bypass intended database-query restrictions and perform NULL checks or trigger missing WHERE clauses via a crafted request that leverages (1) third-party Rack middleware or (2) custom Rack middleware. NOTE: this vulnerability exists because of an incomplete fix for CVE-2013-0155.

Incomplete fix to CVE-2013-0155 (Unsafe Query Generation Risk) Due to the way that `Rack::Request` and `Rails::Request` interact, it is possible for a 3rd party or custom rack middleware to parse the parameters insecurely and store them in the same key that Rails uses for its own parameters. In the event that happens the application will receive unsafe parameters and could be vulnerable to the earlier vulnerability: it would be possible for an attacker to issue unexpected database queries with `IS NULL` or empty where clauses.