Microsoft ISA Server Web Proxy DoS Vulnerability
BID:2600
Info
Microsoft ISA Server Web Proxy DoS Vulnerability
| Bugtraq ID: | 2600 |
| Class: | Boundary Condition Error |
| CVE: | |
| Remote: | Yes |
| Local: | Yes |
| Published: | Apr 16 2001 12:00AM |
| Updated: | Apr 16 2001 12:00AM |
| Credit: | Discovered by Richard Reiner, Graham Wiseman, Matthew Siemens and Kent Nicolson of SecureXpert Labs. Posted in a Microsoft Security Bulletin MS01-021 on April 16, 2001. |
| Vulnerable: |
Microsoft ISA Server 2000 |
| Not Vulnerable: | |
Discussion
Microsoft ISA Server Web Proxy DoS Vulnerability
It is possible for a user to cause the Web Proxy service on a host running MS ISA Server to stop responding.
If a HTTP request with an unusually long path is submitted, the Web Proxy service could stop responding.
This vulnerability is only exploitable from the internal network unless the Web Publishing service has been enabled, in which case it can be exploited from either internal or external networks. It is disabled by default.
A HTML email containing the malicious URL in an image tag or a javascript URL, could invoke a user's browser. An attempt to fulfill this request by the Web Proxy service, could instigate the denial of service condition on an internal users system. This is a potential way a remote attacker could exploit this vulnerability even if Web Publishing is disabled.
* It has been reported that the execution of arbitrary commands is possible. If this is the case the complete remote compromise of the host may be achievable. The latest findings have not been confirmed by anyone other than the person who posted about it.
It is possible for a user to cause the Web Proxy service on a host running MS ISA Server to stop responding.
If a HTTP request with an unusually long path is submitted, the Web Proxy service could stop responding.
This vulnerability is only exploitable from the internal network unless the Web Publishing service has been enabled, in which case it can be exploited from either internal or external networks. It is disabled by default.
A HTML email containing the malicious URL in an image tag or a javascript URL, could invoke a user's browser. An attempt to fulfill this request by the Web Proxy service, could instigate the denial of service condition on an internal users system. This is a potential way a remote attacker could exploit this vulnerability even if Web Publishing is disabled.
* It has been reported that the execution of arbitrary commands is possible. If this is the case the complete remote compromise of the host may be achievable. The latest findings have not been confirmed by anyone other than the person who posted about it.
Exploit / POC
Microsoft ISA Server Web Proxy DoS Vulnerability
The following exploit is meant to be launched from a Linux system and has been provided by SecureXpert DIRECT Bulletin Service <[email protected]>:
The following exploit is meant to be launched from a Linux system and has been provided by SecureXpert DIRECT Bulletin Service <[email protected]>:
Solution / Fix
Microsoft ISA Server Web Proxy DoS Vulnerability
Solution:
Microsoft has released a patch which rectifies this issue:
Microsoft ISA Server 2000
Solution:
Microsoft has released a patch which rectifies this issue:
Microsoft ISA Server 2000
References
Microsoft ISA Server Web Proxy DoS Vulnerability
References:
References:
- Microsoft Security Bulletin MS01-021 (Microsoft)