Posted by Virus Bulletin on Dec 15, 2011
Vulnerability 'not worthy of bug bounty program'.
Researchers at Solera Labs have discovered spammers using an open redirect at Google to hide the final destination of their link from both users and filters.
Open redirects on a domain allow for the creation of redirects to arbitrary third-party sites. They are usually enabled by a site's administrator to measure click-through rates, though in practice there is rarely ever a need for them to be open. When they are, they have a history of being abused by spammers who thus avoid their emails being blocked because of a blacklisted domain name.
The redirects are still open at time of writing. Google has a famous 'bug bounty' program, offering rewards to those pointing out bugs in its products and services. Open redirects, however, are excluded from the program because Google claims that even without a redirect, a user can be tricked into believing a link or website is genuine.
While this may be true, it ignores another reason why open redirects are attractive for spammers: with the increasing importance of URL and domain reputation in spam filtering, spammers may not care so much about tricking the user into believing their link is genuine, but they do care about filters not seeing their malicious websites.
More at Solera Labs' blog here, which also includes a brief analysis of the fake AV the victim is ultimately redirected to. Google's views on open redirects can be found here.
Posted on 15 December 2011 by Virus Bulletin