Zendframework Potential Information Disclosure and Insufficient Entropy vulnerability

Impact

In Zend Framework, Zend_Captcha_Word (v1) and Zend\Captcha\Word (v2) generate a "word" for a CAPTCHA challenge by selecting a sequence of random letters from a character set. Prior to this advisory, the selection was performed using PHP's internal array_rand() function. This function does not generate sufficient entropy due to its usage of rand() instead of more cryptographically secure methods such as openssl_pseudo_random_bytes(). This could potentially lead to information disclosure should an attacker be able to brute force the random number generation.

Affected packages

Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.

Original source description

References

• Security advisory framework.zend.com/security/advisory/ZF2015-09
• Security advisory github.com/FriendsOfPHP/security-advisories/blob/master/zendframework/zendframework1/ZF2015-09.yaml
• Source reference github.com/zendframework/zf1