A vulnerability has been found in the SilverStripe framework where a login url can be potentially redirected to an external site.

For example, the url http://www.my-silverstripe-site.com/Security/login?BackURL=/\attacker-site.com will redirect successful logins to the page http://attacker-site.com. If that website were set up to look identical to the first with "login failed" then the user will likely just enter their user/pass again.

References

• silverstripe/silverstripe-framework@22a35e4
• silverstripe/silverstripe-framework@c14e7f6
• https://github.com/FriendsOfPHP/security-advisories/blob/master/silverstripe/framework/SS-2015-012-1.yaml
• https://www.silverstripe.org/software/download/security-releases/ss-2015-012