Title: Microsoft Windows showHelp CHM File Execution Weakness
Severity: HIGH
Description:
Microsoft Windows is prone to a security flaw in the implementation of the showHelp() method. Microsoft previously released patches that provide security measures to prevent abuse of the showHelp() method to reference local compiled help files (.CHM) from within a web page. This initial problem was described in BID 6780/MS03-004. However, using directory traversal sequences and special syntax when referring to the CHM file, it is possible to bypass this restriction.
To exploit this issue, the directory traversal sequences must form a relative path to the resource. By appending two colons (::) to the name of the compiled help file (which will have a file extension other than .CHM), the browser will interpret the file as a compiled help file. This would occur in the context of the Local Zone. The attacker would still need a method to place the file in a known location on the victim system and a way to run executable content referenced by the .CHM file. However, there are known issues in Internet Explorer (such as BID 8984) which be exploited in combination with this weakness with the end result of installing and executing malicious code on the client system.
** UPDATE: This issue was initially believed to affect Microsoft Internet Explorer but is actually an operating system issue. Microsoft Internet Explorer, Outlook, and Outlook Express may all present attack vectors for this security flaw.
Affected Products:
- Avaya DefinityOne Media Servers
- Avaya IP600 Media Servers
- Avaya S3400 Message Application Server
- Avaya S8100 Media Servers
- Microsoft Internet Explorer 5.5
- Microsoft Internet Explorer 5.5 SP1
- Microsoft Internet Explorer 5.5 SP2
- Microsoft Internet Explorer 6.0
- Microsoft Internet Explorer 6.0 SP1
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Advanced Server SP1
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Advanced Server SP3
- Microsoft Windows 2000 Advanced Server SP4
- Microsoft Windows 2000 Datacenter Server
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Datacenter Server SP3
- Microsoft Windows 2000 Datacenter Server SP4
- Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Professional SP1
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Professional SP3
- Microsoft Windows 2000 Professional SP4
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Server SP1
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Server SP3
- Microsoft Windows 2000 Server SP4
- Microsoft Windows 2000 Terminal Services
- Microsoft Windows 2000 Terminal Services SP1
- Microsoft Windows 2000 Terminal Services SP2
- Microsoft Windows 98
- Microsoft Windows 98SE
- Microsoft Windows ME
- Microsoft Windows NT Enterprise Server 4.0
- Microsoft Windows NT Enterprise Server 4.0 SP1
- Microsoft Windows NT Enterprise Server 4.0 SP2
- Microsoft Windows NT Enterprise Server 4.0 SP3
- Microsoft Windows NT Enterprise Server 4.0 SP4
- Microsoft Windows NT Enterprise Server 4.0 SP5
- Microsoft Windows NT Enterprise Server 4.0 SP6
- Microsoft Windows NT Enterprise Server 4.0 SP6a
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Server 4.0 SP1
- Microsoft Windows NT Server 4.0 SP2
- Microsoft Windows NT Server 4.0 SP3
- Microsoft Windows NT Server 4.0 SP4
- Microsoft Windows NT Server 4.0 SP5
- Microsoft Windows NT Server 4.0 SP6
- Microsoft Windows NT Server 4.0 SP6a
- Microsoft Windows NT Terminal Server 4.0
- Microsoft Windows NT Terminal Server 4.0 SP1
- Microsoft Windows NT Terminal Server 4.0 SP2
- Microsoft Windows NT Terminal Server 4.0 SP3
- Microsoft Windows NT Terminal Server 4.0 SP4
- Microsoft Windows NT Terminal Server 4.0 SP5
- Microsoft Windows NT Terminal Server 4.0 SP6
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Workstation 4.0 SP1
- Microsoft Windows NT Workstation 4.0 SP2
- Microsoft Windows NT Workstation 4.0 SP3
- Microsoft Windows NT Workstation 4.0 SP4
- Microsoft Windows NT Workstation 4.0 SP5
- Microsoft Windows NT Workstation 4.0 SP6
- Microsoft Windows NT Workstation 4.0 SP6a
- Microsoft Windows Server 2003 Datacenter Edition
- Microsoft Windows Server 2003 Datacenter Edition Itanium
- Microsoft Windows Server 2003 Enterprise Edition
- Microsoft Windows Server 2003 Enterprise Edition Itanium
- Microsoft Windows Server 2003 Standard Edition
- Microsoft Windows Server 2003 Web Edition
- Microsoft Windows XP 64-bit Edition
- Microsoft Windows XP 64-bit Edition SP1
- Microsoft Windows XP 64-bit Edition Version 2003
- Microsoft Windows XP 64-bit Edition Version 2003 SP1
- Microsoft Windows XP Home
- Microsoft Windows XP Home SP1
- Microsoft Windows XP Professional
- Microsoft Windows XP Professional SP1
References:
- CERT/CC: Technical Cyber Security Alert TA04-196A
- CERT/CC: Vulnerability Note VU#187196
- Microsoft: Microsoft Security Bulletin MS04-023
Juniper Networks provides this content via a wide variety of sources and production methods. If notified of errors or omissions in the content of this page, Juniper Networks, at its discretion, will modify or remove the page or leave the content as is, depending on various factors including but not limited to the reputation and authority of the party providing the notification. Please use the contact information displayed elsewhere on this page to report any errors or omissions regarding the content on this page.
