2106051 : Microsoft IIS 4.0/5.0 escaped percent found

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Event description Jump to the top of this document

Microsoft IIS (Internet Information Server) versions 4.0 and 5.0 incorrectly evaluate URLs twice for escape sequences. In an attempt to bypass intrusion detection systems, an attacker may submit to an IIS server a URL containing escape sequences (such as %25) representing percent (%) characters.

Products that have this security check Jump to the top of this document

HTTP_IIS_Double_Eval_Evasion

This signature detects a URL request containing encoded escaped sequences, such as "%25". Such a request could indicate an attacker's attempt to use escaped sequences to bypass an intrusion detection system. See also HTTP_IIS_Percent_Evasion, HTTP_IIS_Unicode_Evasion, and HTTP_IIS_UTF8_Evasion.


Affected platforms Jump to the top of this document

How to remove this vulnerability Jump to the top of this document

No remedy available as of October 2001.

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This page was created on Thu Jun 11 09:06:52 2009