{"action":"created","issue":{"url":"https://api.github.com/repos/joomla/joomla-cms/issues/8329","labels_url":"https://api.github.com/repos/joomla/joomla-cms/issues/8329/labels{/name}","comments_url":"https://api.github.com/repos/joomla/joomla-cms/issues/8329/comments","events_url":"https://api.github.com/repos/joomla/joomla-cms/issues/8329/events","html_url":"https://github.com/joomla/joomla-cms/issues/8329","id":115711640,"number":8329,"title":"JCryptCipher - Chosen Ciphertext Attacks","user":{"login":"paragonie-scott","id":11591518,"avatar_url":"https://avatars.githubusercontent.com/u/11591518?v=3","gravatar_id":"","url":"https://api.github.com/users/paragonie-scott","html_url":"https://github.com/paragonie-scott","followers_url":"https://api.github.com/users/paragonie-scott/followers","following_url":"https://api.github.com/users/paragonie-scott/following{/other_user}","gists_url":"https://api.github.com/users/paragonie-scott/gists{/gist_id}","starred_url":"https://api.github.com/users/paragonie-scott/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/paragonie-scott/subscriptions","organizations_url":"https://api.github.com/users/paragonie-scott/orgs","repos_url":"https://api.github.com/users/paragonie-scott/repos","events_url":"https://api.github.com/users/paragonie-scott/events{/privacy}","received_events_url":"https://api.github.com/users/paragonie-scott/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":4,"created_at":"2015-11-08T06:19:48Z","updated_at":"2015-11-09T02:30:22Z","closed_at":null,"body":"None of the JCrypt implementations are properly [authenticating the ciphertext](https://paragonie.com/blog/2015/05/using-encryption-and-authentication-correctly). As a result, an active attacker can flip bits at will until they get a useful result. Combine the CCA with #8328 and you get a nice padding oracle attack against the Rijndael256-CBC encryption.\r\n\r\nFurther reading: \r\n\r\n* http://web.engr.oregonstate.edu/~rosulekm/crypto/12-cca.pdf\r\n* http://tonyarcieri.com/all-the-crypto-code-youve-ever-written-is-probably-broken\r\n* http://crypto.stackexchange.com/questions/1263/how-does-a-chosen-ciphertext-attack-work-with-a-simple-example\r\n\r\nTL;DR Encrypt then MAC. See how [defuse/php-encryption](https://github.com/defuse/php-encryption) implements its encryption and authentication. (In fact, I highly recommend switching to that and exercising liberal use of your delete key on the existing cryptography code.)"},"comment":{"url":"https://api.github.com/repos/joomla/joomla-cms/issues/comments/154904460","html_url":"https://github.com/joomla/joomla-cms/issues/8329#issuecomment-154904460","issue_url":"https://api.github.com/repos/joomla/joomla-cms/issues/8329","id":154904460,"user":{"login":"mbabker","id":368545,"avatar_url":"https://avatars.githubusercontent.com/u/368545?v=3","gravatar_id":"","url":"https://api.github.com/users/mbabker","html_url":"https://github.com/mbabker","followers_url":"https://api.github.com/users/mbabker/followers","following_url":"https://api.github.com/users/mbabker/following{/other_user}","gists_url":"https://api.github.com/users/mbabker/gists{/gist_id}","starred_url":"https://api.github.com/users/mbabker/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mbabker/subscriptions","organizations_url":"https://api.github.com/users/mbabker/orgs","repos_url":"https://api.github.com/users/mbabker/repos","events_url":"https://api.github.com/users/mbabker/events{/privacy}","received_events_url":"https://api.github.com/users/mbabker/received_events","type":"User","site_admin":false},"created_at":"2015-11-09T02:30:22Z","updated_at":"2015-11-09T02:30:22Z","body":"Unfortunately the php-encryption library requires PHP 5.4 while we're still in 5.3.10+ world (ya, shoot us ;-) ).  So that's not much of an option."}}