CERT-In Vulnerability Note
CIVN-2009-0156
Microsoft Internet Information Services IIS File Extension Parsing Vulnerability
Original Issue Date:December 30, 2009
Severity Rating: MEDIUM
Systems Affected
- Microsoft Internet Information Services IIS 5
- Microsoft Internet Information Services IIS 6
Overview
A vulnerability has been reported in Microsoft Internet Information Services IIS which could allow remote attacker to execute any extension as an Active Server Page ASP or any other executable extension on the affected server.
Description
This vulnerability is caused due to improper handling of files with multiple extensions separated by semicolon character ";" e.g. malicious.asp;.jpg as ASP file.
A remote attacker could exploit this vulnerability by uploading malicious executable files on vulnerable server, bypassing file extension protections and restrictions. Successful exploitation of this vulnerability could allow remote attacker to execute malicious executables and to take complete control of the vulnerable web server.
Workaround
- Remove "execute" permissions from the upload folders
Vendor Information
Microsoft
http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx
References
Microsoft
http://blogs.technet.com/msrc/archive/2009/12/27/new-reports-of-a-vulnerability-in-iis.aspx
http://msdn.microsoft.com/en-us/library/ms994921.aspx
http://technet.microsoft.com/en-us/library/cc782762 WS.10 .aspx
SECPROJECT
http://soroush.secproject.com/downloadable/iis-semicolon-report.pdf
CERT-In
knowledgebase/guidelines/CISG-2006-01
SANS
http://isc.sans.org/diary.html?storyid=7810
Secunia
http://secunia.com/advisories/37831/
VUPEN
http://www.vupen.com/english/advisories/2009/3634
Disclaimer
The information provided herein is on "as is" basis, without warranty of any kind.
Contact Information
Email: info@cert-in.org.in Phone: +91-11-2436857
Postal address
Indian Computer Emergency Response Team (CERT-In)
Ministry of Electronics and Information Technology
Government of India
Electronics Niketan
6, CGO Complex, Lodhi Road,
New Delhi - 110 003
India
|