To quote the release...
"Microsoft is investigating a new public report of a vulnerability in ASP.NET. An attacker who exploited this vulnerability could view data, such as the View State, which was encrypted by the target server, or read data from files on the target server, such as web.config. This would allow the attacker to tamper with the contents of the data. By sending back the altered contents to an affected server, the attacker could observe the error codes returned by the server. We are not aware of attacks that try to use the reported vulnerabilities or of customer impact at this time."
A few more details are available at Scott Guthrie's Blog
-- Rick Wanner - rwanner at isc dot sans dot org - http://rwanner.blogspot.com/
Sep 18th 2010
8 years ago
MS ASP.NET advisory • V1.2 ...
• V1.2 (September 24, 2010): Added an entry to the FAQ to announce a revision to the workaround, "Enable a UrlScan or Request Filtering rule, enable ASP.NET custom errors, and map all error codes to the same error page." Customers who have already applied the workaround should -reapply- all listed steps...
24 Sep 2010
Sep 24, 2010
Sep 25th 2010
7 years ago