Microsoft IIS Semi-Colon Vulnerability

I found a vulnerability in Microsoft IIS when I was searching about a method to execute an ASP file when we can only upload a JPG file.

The result was too simple, but interesting! I need only a semicolon between the “.asp” and the “.jpg” to execute an ASP file. So, the answer was “myfilename.asp;,jpg”. I have written some information about this vulnerability in:

https://soroush.me/downloadable/iis-semicolon-report.pdf

I’ll try to update this PDF file if there was a need to add or change some information.

Description of this vulnerability from Secunia.com is:

There are also several websites which wrote about this weakness:

1. Secunia Advisory: Microsoft IIS ASP Multiple Extensions Security Bypass

2. Securityfocus: Microsoft IIS Malformed Local Filename Security Bypass Vulnerability

3. The Register: Microsoft IIS vuln leaves users open to remote attack

4. VUPEN Security: Microsoft IIS File Extension Processing Security Bypass Vulnerability

5. Securitytracker: Microsoft Internet Information Services (IIS) Filename Extension Parsing Flaw May Let Users Bypass Security Controls