Microsoft ISA Server 2000 FTP Bounce Filtering Vulnerability

Bugtraq ID:	10484
Class:	Design Error
CVE:
Remote:	Yes
Local:	No
Published:	Nov 12 2003 12:00AM
Updated:	Nov 12 2003 12:00AM
Credit:	The vendor announced this vulnerability.
Vulnerable:	Microsoft ISA Server 2000 SP1 + Microsoft Small Business Server 2000 0 + Microsoft Small Business Server 2003 Premium Edition - Microsoft Windows 2000 Advanced Server SP2 - Microsoft Windows 2000 Advanced Server SP1 - Microsoft Windows 2000 Datacenter Server SP2 - Microsoft Windows 2000 Datacenter Server SP1 - Microsoft Windows 2000 Server SP2 - Microsoft Windows 2000 Server SP1 Microsoft ISA Server 2000 + Microsoft Small Business Server 2000 0 + Microsoft Small Business Server 2003 Premium Edition - Microsoft Windows 2000 Advanced Server - Microsoft Windows 2000 Server
Not Vulnerable:	Microsoft ISA Server 2000 SP2 + Microsoft Small Business Server 2000 0 + Microsoft Small Business Server 2003 Premium Edition

Microsoft ISA Server 2000 FTP Bounce Filtering Vulnerability

Microsoft ISA Server improperly allows FTP bounce attacks through its ftp application filter component.

This vulnerability manifests itself if an FTP server affected by BID 126, also described in the CERT advisory CA-1997-27, is protected by Microsoft ISA Server.

An FTP server that is vulnerable to the FTP bounce attack can be used by an attacker to bypass IP based access controls.

This issue is not present if an FTP server is not used.

Microsoft ISA Server 2000 FTP Bounce Filtering Vulnerability

No exploit is required.

Microsoft ISA Server 2000 FTP Bounce Filtering Vulnerability

Solution:
Microsoft has released a service pack to address this vulnerability and other issues.


Microsoft ISA Server 2000 SP1

• Microsoft Internet Security and Acceleration (ISA) Server 2000 Service Pack 2
  http://www.microsoft.com/downloads/details.aspx?FamilyID=c8d3d98b-1cd4 -406a-a04a-2aa2547d09a3&DisplayLang=en