Microsoft has released a security bulletin and updated software to address the invalid pointer reference access arbitrary code execution vulnerability in Microsoft Internet Explorer.
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.
This vulnerability exists due to unsafe memory operations performed during the processing of malformed web pages. An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a malicious website. If successful, the attacker could execute arbitrary code with the privileges of the user.
Functional exploit code is being used in ongoing exploits.
Microsoft has confirmed this vulnerability in a security bulletin and released updated software.
Warning Indicators
Microsoft Internet Explorer versions 6.0 SP1 and prior and 7.0 are vulnerable when running on the following 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 x64 Edition SP2 and prior
Windows Server 2003 for Itanium-based Systems SP2 and prior
Windows Vista SP2 and prior
Windows Vista x64 Edition SP2 and prior
Windows Server 2008 for 32-bit Systems SP2 and prior
Windows Server 2008 for x64-based Systems SP2 and prior
IntelliShield Analysis
An attacker cannot directly exploit this vulnerability and instead must rely upon user interaction in order to accomplish an exploit. The attacker must convince a user to view a malicious website. The attacker is likely to provide links to the malicious website within e-mail or instant messages delivered to the user, possibly using social engineering techniques to convince users to follow the link.
Reports indicate that some attacks have originated from websites at the domain topix21century.com. Such attacks attempt to exploit the vulnerability to install malicious software on vulnerable systems. Exploits are currently limited and targeted, but may expand. Administrators are advised to implement mitigations as soon as possible.
Systems that restrict user privileges may be less impacted in the event of an exploit, as any code execution would run in a limited security context.
Internet Explorer 8 is unaffected by the vulnerability. Although patches for previous versions are not yet available, upgrading to Internet Explorer 8 could prevent exploitation.
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS10-018
Microsoft has re-released a security advisory at the following link: 981374
US-CERT has released a vulnerability note at the following link: VU#744549
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If that user holds elevated privileges, the attacker could completely compromise the system.
Technical Information
This vulnerability is due to a use-after-free memory error during the processing of malformed web content by Internet Explorer using functions in the iepeers.dll library. The processing of a malicious website could cause Internet Explorer to access a previously deleted memory pointer, resulting in memory corruption. An unauthenticated, remote attacker could exploit the vulnerability by convincing the user to view a malicious website. If successful, the attacker could trigger memory corruption that could allow the attacker to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the appropriate updates.
Administrators may consider configuring Internet Explorer to prompt users before running Active Scripting or ActiveX controls by setting the Internet and Local Intranet security zone settings to High. Alternately, administrators could disable Active Scripting and ActiveX controls in these security zones.
Users are advised to run applications with the least necessary privileges.
Users should verify that unsolicited links are safe to follow.
Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
Administrators may consider disabling JavaScript in the vulnerable applications.
Cisco Security Research and Operations has tested Cisco Security Agent to verify that it prevents the malicious actions initiated by active exploitation of this vulnerability. As a result, system compromise is mitigated. Based on the characteristics of this vulnerability, Cisco expects that Cisco Security Agent will prevent other similar attempts of exploitation as well.
Patches/Software
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.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Version 3, March 15, 2010, 8:53 AM: Microsoft has re-released a security advisory and updated software to address the Microsoft Internet Explorer invalid pointer reference access arbitrary code execution vulnerability.
Version 2, March 10, 2010, 10:20 AM: Additional technical information is available to describe the Microsoft Internet Explorer arbitrary code execution vulnerability. US-CERT has released a vulnerability note related to the vulnerability. Functional exploit code exists.
Version 1, March 9, 2010, 2:49 PM: Microsoft Internet Explorer contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are not available.
Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base
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