|
|
|
|
| |
| A vulnerability in IE and Windows Scripting Host enables attackers to run code of her choice, if user visited attacker's web site or opened an HTML e-mail from the attacker. Three other vulnerabilities, of lesser severity and exploitable in more restricted circumstances, also are eliminated by the patches below. |
| |
Credit:
This was reported by Oliver Friedrichs
For additional information see Microsoft Security Bulletin MS01-015: http://www.microsoft.com/technet/security/bulletin/ms01-015.asp
|
| |
Vulnerable systems:
Microsoft Internet Explorer 5.01
Microsoft Internet Explorer 5.5
Microsoft Windows Scripting Host 5.1
Microsoft Windows Scripting Host 5.5
The IE security architecture provides a caching mechanism that is used to store content that needs to be downloaded and processed on the user's local machine. The purpose of the cache is to obfuscate the physical location of the cached content, in order to ensure that the web page or HTML e-mail will work through the IE security architecture to access the information. This ensures that the uses of the information can be properly restricted.
A vulnerability exists because it is possible for a web page or HTML e-mail to learn the physical location of cached content. Armed with this information, an attacker could cause the cached content to be opened in the Local Computer Zone. This would enable him to launch compiled HTML help (.CHM) files that contain shortcuts to executables, thereby enabling him to run the executables.
In addition to eliminating this vulnerability, the patches provided below eliminate three other vulnerabilities that either pose significantly less risk or could only be exploited in very restricted situations:
- A variant of the Frame Domain Verification vulnerability. The vulnerability could enable a malicious web site operator to open two browser windows, one in the web site's domain and the other on the user's local file system, and to pass information from the latter to the former. This could enable the web site operator to read, but not change, any file on the user's local computer that could be opened in a browser window.
- A vulnerability that is identical in effect to the "Frame Domain Verification" vulnerability, but which actually results from a flaw in Windows Scripting Host rather than IE.
- A vulnerability that affects how Telnet sessions are invoked via IE. By design, telnet sessions can be launched via IE. However, a vulnerability exists because when doing so, IE will start Telnet using any command-line options the web site specifies. This only becomes a concern when using the version of the Telnet client that installs as part of Services for Unix (SFU) 2.0 on Windows NT(r) 4.0 or Windows(r) 2000 machines. The version of the Telnet client in SFU 2.0 provides an option for creating a verbatim transcript of a Telnet session. An attacker could start a session using the logging option, then stream an executable file onto the user's system in a location that would cause it to be executed automatically the next time the user booted the machine. The flaw does not lie in the Telnet client, but in IE, which should not allow Telnet to be started remotely with command-line arguments.
Mitigating Factors:
- None of the vulnerabilities could be exploited without some user action - either browsing to the attacker's site or opening a mail from him. Customers who exercise safe browsing habits would be less likely visit untrustworthy sites, and customers who have used the Security Zones feature to restrict what HTML mail can do would be less likely to be affected by this vulnerability.
- The variants of the "frame domain verification" vulnerability discussed above could only be used to view files, and only file types that can be opened in a browser window.
- The vulnerability affecting Telnet invocation is only a concern for customers who are using the Telnet client that ships as part of Services for Unix 2.0. Other versions of Telnet do not include the command-line feature to create log files.
Patch Availability:
Cached content identification vulnerability and new variant of "frame domain verification" vulnerability:
http://www.microsoft.com/windows/ie/download/critical/q286045/default.asp
Note: Microsoft recommends that all customers install this patch.
Windows Scripting Host vulnerability:
Windows Scripting Host 5.1:
http://www.microsoft.com/msdownload/vbscript/scripting51.asp
Windows Scripting Host 5.5:
http://www.microsoft.com/msdownload/vbscript/scripting.asp
Note: Microsoft recommends that all customers install the patch for their version of Windows Scripting Host.
Telnet invocation vulnerability:
http://www.microsoft.com/windows/ie/download/critical/q286043/default.asp
Note: Microsoft recommends that customers who have installed Services for Unix 2.0 install this patch.
|
|
|
|
|
|
|
