Microsoft Internet Explorer contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are available.
Description
Microsoft Internet Explorer versions 6.0 SP1 and prior and 7.0 contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability exists due to insufficient handling of arguments passed to print previews. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to visit a malicious website that is designed to trigger memory corruption in Internet Explorer when viewed. The resulting error condition could allow the attacker to execute arbitrary code with the privileges of the user.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
Warning Indicators
Microsoft Internet Explorer versions 6.0 SP1 and prior and 7.0 are vulnerable on the following operating systems:
Windows 2000 SP4 and prior
Windows XP SP3 and prior
Windows XP Professional x64 Edition SP2 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 for Itanium-based Systems SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Vista SP1 and prior
Windows Vista x64 Edition SP1 and prior
Windows Server 2008 for 32-bit Systems
Windows Server 2008 for x64-based Systems
Windows Server 2008 for Itanium-based Systems
IntelliShield Analysis
In order to exploit this vulnerability, an attacker must convince a user to visit a malicious website. Attackers may provide links within e-mail messages or post links on public websites. If the user follows the provided link, the attacker could execute arbitrary code with the privileges of the user. If the user has Administrator privileges, the attacker could execute arbitrary code, resulting in the complete compromise of the affected system. Failed exploit attempts may cause Internet Explorer to close; however, this has not been confirmed. It is also unclear as to whether or not the targeted user must select Print Preview for memory corruption to occur or if just viewing the web page triggers the flaw.
Systems on which administrators have deployed anti-intrusion measures, such as reduced-privilege user accounts and host-based intrusion detection systems, are at a reduced risk. User education can also play a significant role in preventing exploitation. In addition, Windows Vista systems are less likely to be affected due to the default restrictions placed on user accounts. Windows Server 2003 systems running Internet Explorer are also at a reduced risk for exploitation due to the Enhanced Security Configuration mode. The Enhanced Security Configuration mode sets the Internet security level to High by default, reducing the impact for web pages that are not yet included in the trusted sites zone.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the August 2008 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin for August 2008
Microsoft has resolved this vulnerability by improving argument validation when processing print previews.
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS08-045
Impact
An unauthenticated, remote attacker could exploit this vulnerability to cause Internet Explorer to crash or execute arbitrary code with the privileges of the user. On systems that grant users Administrator privileges, an attacker could execute code that may result in the complete compromise of the affected system. Systems running Windows Vista are less likely to be affected due to the additional controls placed on user accounts by default.
Technical Information
The vulnerability exists due to a memory corruption error when Internet Explorer attempts to validate arguments passed to print previews. An unauthenticated, remote attacker could trigger the corruption of process memory by convincing a user to visit a malicious web page that is designed to cause the browser to pass malicious arguments to print previews. This memory operation could corrupt Internet Explorer memory in such a way as to allow an attacker to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the appropriate software updates.
Users are advised not to open e-mail from untrusted sources.
Users are advised not to follow unsolicited links. Users should verify the authenticity of an unexpected link from a trusted source prior to following it.
Users are advised to run applications with the least necessary privileges.
Patches/Software
Microsoft has released updated software at the following links:
Datacenter Edition Base | Datacenter Edition, 64-bit Base | Enterprise Edition Base | Enterprise Edition, 64-bit Base | Itanium-Based Systems Edition Base | Standard Edition Base | Standard Edition, 64-bit Base | Web Server Base | Web Server, 64-bit Base
Microsoft, Inc.
Windows Vista
Business Base, SP1 | Business x64 Edition Base, SP1 | Enterprise Base, SP1 | Enterprise x64 Edition Base, SP1 | Home Basic Base, SP1 | Home Basic x64 Edition Base, SP1 | Home Premium Base, SP1 | Home Premium x64 Edition Base, SP1 | Ultimate Base, SP1 | Ultimate x64 Edition Base, SP1
Microsoft, Inc.
Windows XP
Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base, SP2
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