Microsoft IIS Authentication Method Disclosure Vulnerability
BID:4235
Info
Microsoft IIS Authentication Method Disclosure Vulnerability
| Bugtraq ID: | 4235 |
| Class: | Design Error |
| CVE: |
CVE-2002-0419 |
| Remote: | Yes |
| Local: | No |
| Published: | Mar 05 2002 12:00AM |
| Updated: | Jul 11 2009 10:56AM |
| Credit: | Published by David Litchfield ([email protected]) of Next Generation Security Software. |
| Vulnerable: |
Microsoft IIS 5.1 Microsoft IIS 5.0 Microsoft IIS 4.0 alpha Microsoft IIS 4.0 |
| Not Vulnerable: | |
Discussion
Microsoft IIS Authentication Method Disclosure Vulnerability
Microsoft IIS supports Basic and NTLM authentication. Reportedly, the authentication methods supported by a given IIS server can be revealed to an attacker through the inspection of returned error messages, even when anonymous access is also granted.
When a valid authentication request is submitted for either message with an invalid username and password, an error message will be returned. This happens even if anonymous access to the requested resource is allowed. An attacker may be able to use this information to launch further intelligent attacks against the server, or to launch a brute-force password attack against a known username.
Microsoft IIS supports Basic and NTLM authentication. Reportedly, the authentication methods supported by a given IIS server can be revealed to an attacker through the inspection of returned error messages, even when anonymous access is also granted.
When a valid authentication request is submitted for either message with an invalid username and password, an error message will be returned. This happens even if anonymous access to the requested resource is allowed. An attacker may be able to use this information to launch further intelligent attacks against the server, or to launch a brute-force password attack against a known username.
Exploit / POC
Microsoft IIS Authentication Method Disclosure Vulnerability
No exploit is required. The following HTTP requests have been provided as examples by David Litchfield ([email protected]):
GET / HTTP/1.1
Host: iis-server
Authorization: Basic cTFraTk6ZDA5a2xt
GET / HTTP/1.1
Host: iis-server
Authorization: Negotiate TlRMTVNTUAABAAAAB4IAoAAAAAAAAAAAAAAAAAAAAAA=
No exploit is required. The following HTTP requests have been provided as examples by David Litchfield ([email protected]):
GET / HTTP/1.1
Host: iis-server
Authorization: Basic cTFraTk6ZDA5a2xt
GET / HTTP/1.1
Host: iis-server
Authorization: Negotiate TlRMTVNTUAABAAAAB4IAoAAAAAAAAAAAAAAAAAAAAAA=
Solution / Fix
Microsoft IIS Authentication Method Disclosure 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]
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]
References
Microsoft IIS Authentication Method Disclosure Vulnerability
References:
References:
- Considerations for IIS Authentication (NGSSoftware)