CVE-2014-4671

Adobe Flash Player before 13.0.0.231 and 14.x before 14.0.0.145 on Windows and OS X and before 11.2.202.394 on Linux, Adobe AIR before 14.0.0.137 on Android, Adobe AIR SDK before 14.0.0.137, and Adobe AIR SDK & Compiler before 14.0.0.137 do not properly restrict the SWF file format, which allows remote attackers to conduct cross-site request forgery (CSRF) attacks against JSONP endpoints, and obtain sensitive information, via a crafted OBJECT element with SWF content satisfying the character-set requirements of a callback API.

Weakness

The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

Affected Software

Potential Mitigations

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330]
• Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
• Use the “double-submitted cookie” method as described by Felten and Zeller:
• When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user’s machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same.
• Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult.
• This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/111.html
• https://cwe.mitre.org/data/definitions/462.html
• https://cwe.mitre.org/data/definitions/467.html
• https://cwe.mitre.org/data/definitions/62.html

References

• http://helpx.adobe.com/security/products/flash-player/apsb14-17.html
• http://miki.it/blog/2014/7/8/abusing-jsonp-with-rosetta-flash/
• http://rhn.redhat.com/errata/RHSA-2014-0860.html
• http://secunia.com/advisories/59774
• http://secunia.com/advisories/59837
• http://security.gentoo.org/glsa/glsa-201407-02.xml
• http://www.securityfocus.com/bid/68457
• http://www.securitytracker.com/id/1030533