The CVSS score for this alert has been modified to reflect higher exploitability. Information about the malware that exploits this vulnerability is also available.
Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the targeted system.
The vulnerability exists because the affected operating systems incorrectly process .lnk files. An unauthenticated, remote attacker could exploit the vulnerability by including a crafted .lnk file on local drives or on a remote shared web resource and then persuading a user to browse to the directory of this .lnk file. Successful exploitation could allow the attacker to execute arbitrary code.
A functional exploit that is a part of the Metasploit framework is publicly available.
Microsoft has confirmed this vulnerability and released updated software.
Information about the affected products is available†from the vendor advisory in the Vendor Announcements section of this alert.
Reports suggest that this vulnerability is being exploited in the wild via the stuxnet botnet. This malware reportedly targets industrial control systems. Further information about the malware that exploits the vulnerability is available in IntelliShield Alert 20915.
A functional exploit that is a part of the Metasploit framework demonstrates exploitation of this vulnerability, wherein the crafted .lnk file could link to a WebDAV share. As a result, an attacker could reference any remote web resource and the control of malware is not confined to local drives. This factor could make the exploit much easier and is more likely to be used as an attack vector because the attacker does not need to ensure that malicious code exists on the targeted system.
Reports suggest that documents and web pages embedded with .lnk files could be used as an attack vector to exploit this vulnerability.
Limited user interaction is needed to exploit the vulnerability. By default, Microsoft Windows systems have the AutoRun/AutoPlay features enabled for USB media that could cause Windows Explorer to automatically open the location of the crafted .lnk file, reducing user interaction to simply inserting the USB media on a system. This factor could increase the impact of this vulnerability.
Microsoft has released a security bulletin at the following link: MS10-046
Microsoft has re-released a security advisory at the following link: 2286198
US-CERT has released a vulnerability note at the following link: VU#940193
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code on the targeted system.† The arbitrary code would execute in the context of the user who is logged in.† If the user is logged in as Administrator, the attacker could take complete control of the affected system.
The vulnerability is in the Windows Shell component of the Microsoft Windows operating system as a result of incorrect processing when acquiring icons for .lnk files.†
An unauthenticated, remote attacker could exploit the vulnerability through a malicious .lnk file on local drives or a Web-based Distributed Authoring and Versioning (WebDAV) resource and persuading a targeted user to browse to the location of this file using a file manager such as Windows Explorer.† The crafted .lnk file could specify a path name to locally stored or remotely hosted executable files that could be automatically executed.† A successful exploit could allow the attacker to execute arbitrary code by means of the file to which this crafted .lnk file is linked.
Administrators are advised to apply the appropriate updates.
Administrators are advised to configure antivirus software to scan media upon insertion.†
Administrators may also consider disallowing USB drives or other removable media from sensitive environments.
Users are advised not to plug in USB drives from unknown sources.
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Version 4, August 2, 2010, 2:22 PM: Microsoft has released a security bulletin and updates to address the Windows .lnk file processing arbitrary code execution vulnerability.
Version 3, July 21, 2010, 11:45 AM: Microsoft has re-released a security bulletin with updated workarounds and additional information about attack vectors used to exploit the Microsoft Windows .lnk file processing arbitrary code execution vulnerability.
Version 2, July 20, 2010, 11:13 AM: A Metasploit functional exploit demonstrates exploitation of the Microsoft Windows .lnk file processing arbitrary code execution vulnerability via a remote WebDAV share.
Version 1, July 19, 2010, 12:38 PM: Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are not available.
Home Edition Base, SP3 | Professional Edition Base, SP3 | Professional Edition, 64-bit (Itanium) Base, SP2 | Professional x64 (AMD/EM64T) Base, SP2
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.