DNS-based attacks against browsers have been known about for years. These attacks have received increased attention recently, following the discovery of defects within browser-based DNS pinning defences. So far, discussion has focused on browser issues. However, the same attacks can also be performed against web proxies. Browser-based DNS pinning does not apply when a web proxy is being used, because the DNS look-ups occur on the proxy, not the browser. Hence, even if DNS-based attacks are completely addressed within browsers, the problem is not going to go away altogether. The most significant opportunities for DNS-based attacks are against web users on internal corporate networks, as a means of gaining unauthorised access to sensitive information and web applications on internal intranets. Given that a large proportion of these users access the Internet via a proxy server, attacks against web proxies may represent at least as significant a threat as those against browsers. I've written a short paper which explains the problem, examines possible software-based solutions, and describes the defences that organisations and individuals can use to prevent attacks against them. You can find the paper here: http://www.ngssoftware.com/research/papers/DnsPinningAndWebProxies.pdf Cheers, Dafydd Stuttard Principal Security Consultant NGS Software Ltd -- -- E-MAIL DISCLAIMER The information contained in this email and any subsequent correspondence is private, is solely for the intended recipient(s) and may contain confidential or privileged information. For those other than the intended recipient(s), any disclosure, copying, distribution, or any other action taken, or omitted to be taken, in reliance on such information is prohibited and may be unlawful. If you are not the intended recipient and have received this message in error, please inform the sender and delete this mail and any attachments. The views expressed in this email do not necessarily reflect NGS policy. NGS accepts no liability or responsibility for any onward transmission or use of emails and attachments having left the NGS domain. NGS and NGSSoftware are trading names of Next Generation Security Software Ltd. Registered office address: 52 Throwley Way, Sutton, SM1 4BF with Company Number 04225835 and VAT Number 783096402
