Denial of Service and Unsafe Object Creation Vulnerability in JSON There is a denial of service and unsafe object creation vulnerability in the json gem. This vulnerability has been assigned the CVE identifier CVE-2013-0269. Versions Affected: All. This includes JSON that ships with Ruby 1.9.X-pXXX. Not affected: NONE Fixed Versions: 1.7.7, 1.6.8, 1.5.5 Impact ------ When parsing certain JSON documents, the JSON gem can be coerced in to creating Ruby symbols in a target system. Since Ruby symbols are not garbage collected, this can result in a denial of service attack. The same technique can be used to create objects in a target system that act like internal objects. These "act alike" objects can be used to bypass certain security mechanisms and can be used as a spring board for SQL injection attacks in Ruby on Rails. Impacted code looks like this: JSON.parse(user_input) Where the `user_input` variable will have a JSON document like this: {"json_class":"foo"} The JSON gem will attempt to look up the constant "foo". Looking up this constant will create a symbol. In JSON version 1.7.x, objects with arbitrary attributes can be created using JSON documents like this: {"json_class":"JSON::GenericObject","foo":"bar"} This document will result in an instance of JSON::GenericObject, with the attribute "foo" that has the value "bar". Instantiating these objects will result in arbitrary symbol creation and in some cases can be used to bypass security measures. PLEASE NOTE: this behavior *does not change* when using `JSON.load`. `JSON.load` should *never* be given input from unknown sources. If you are processing JSON from an unknown source, *always* use `JSON.parse`. All users running an affected release should either upgrade or use one of the work arounds immediately. Releases -------- The FIXED releases are available at the normal locations. Workarounds ----------- For users that cannot upgrade, please use the attached patches. If you cannot use the attached patches, change your code from this: JSON.parse(json) To this: JSON.parse(json, :create_additions => false) If you cannot change the usage of `JSON.parse` (for example you're using a gem which depends on `JSON.parse` like multi_json), then apply this monkey patch: module JSON class << self alias :old_parse :parse def parse(json, args = {}) args[:create_additions] = false old_parse(json, args) end end end
json 1.6.8 and json 1.7.7 have now been added to the tree. Please consider json 1.6.8 the stable candidate. =dev-ruby/json-1.6.8
(In reply to comment #1) > json 1.6.8 and json 1.7.7 have now been added to the tree. Please consider > json 1.6.8 the stable candidate. > > =dev-ruby/json-1.6.8 Arches, please test and mark stable.
ppc stable
ppc64 stable
ia64 stable
hppa stable
amd64 stable
x86 stable
sparc stable
s390 stable
arm stable
alpha stable
sh stable
CVE-2013-0269 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2013-0269): The JSON gem 1.7.x before 1.7.7, 1.6.x before 1.6.8, and 1.5.x before 1.5.5 allows remote attackers to cause a denial of service (resource consumption) or bypass the mass assignment protection mechanism via a crafted JSON document that triggers the creation of arbitrary Ruby symbols or certain internal objects, as demonstrated by conducting a SQL injection attack against Ruby on Rails, aka "Unsafe Object Creation Vulnerability."
Ready for vote, I vote NO.
GLSA vote: no, too Closing noglsa.
