It's a common and sensible practice to install records of the form "localhost. IN A 127.0.0.1" into nameserver configurations, bizarrely however, administrators often mistakenly drop the trailing dot,
introducing an interesting variation of Cross-Site Scripting (XSS) I call Same-Site Scripting. The missing dot indicates that the record is not fully qualified, and thus queries of the form "localhost.example.com" are resolved. While superficially this may appear to be harmless, it does in fact allow an attacker to cheat the RFC2109 (HTTP State Management Mechanism) same origin restrictions, and therefore hijack state management data.
Sunday, January 20, 2008
Posted by Peter Risdon at 10:39 pm