Loop Back Check

今天遇到一个问题, 修改host文件访问本机遇到http 401.1。

经过排查发现是一个叫做loop back check检查的配置的原因.

什么是loop back check呢?

这个配置是用来防止reflection attack的. 这个配置生效之后, 使用FQDN或者自定义的host header(与机器名不匹配)时, 那么NTLM认证会失败.

那么什么是reflection attack呢?

这种攻击的主要思想就是使用trick, 让被攻击的机器提供给attacker它自己的challenge的答案.

过程如下:

1. The attacker initiates a connection to a target.
2. The target attempts to authenticate the attacker by sending it a challenge.
3. The attacker opens another connection to the target, and sends the target this challenge as its own.
4. The target responds to the challenge.
5. The attacker sends that response back to the target on the original connection.

参考资料:

Reflection attack

http://en.wikipedia.org/wiki/Reflection_attack

You receive error 401.1 when you browse a Web site that uses Integrated Authentication and is hosted on IIS 5.1 or a later version

http://support.microsoft.com/kb/896861

什么是loopback check?

http://www.cnblogs.com/awpatp/archive/2010/03/11/1683672.html