April 11, 2006
Microsoft Internet Explorer is prone to a zone-bypass vulnerability because the browser returns erroneous IOleClientSite when dynamically creating an embedded object. This could cause malicious script code to be executed in a security zone with fewer restrictions than the zone that the content originates from. Attackers may exploit this issue to execute arbitrary code in the context of the currently logged-in user on the affected computer. They may also be able to execute malicious script code in the context of a site that exists in another domain. Attackers may exploit this issue through a malicious web page.
- Microsoft Internet Explorer 5.0.1
- Microsoft Internet Explorer 5.0.1 SP1
- Microsoft Internet Explorer 5.0.1 SP2
- Microsoft Internet Explorer 5.0.1 SP3
- Microsoft Internet Explorer 5.0.1 SP4
- Microsoft Internet Explorer 5.0.1 for Windows 2000
- Microsoft Internet Explorer 5.0.1 for Windows 95
- Microsoft Internet Explorer 5.0.1 for Windows 98
- Microsoft Internet Explorer 5.0.1 for Windows NT 4.0
- Microsoft Internet Explorer 6.0
- Microsoft Internet Explorer 6.0 SP1
- Microsoft Internet Explorer 6.0 SP2 do not use
Run all software as a nonprivileged user with minimal access rights.
Ensure that all non-administrative tasks, such as browsing the web and reading email, are performed as an unprivileged user with minimal access rights.
Do not follow links provided by unknown or untrusted sources.
Users should never visit sites of questionable integrity or follow links provided by unfamiliar or untrusted sources.
Set web browser security to disable the execution of script code or active content.
Disabling scripting and active content in the Internet Zone may limit exposure to this and other vulnerabilities.
Implement multiple redundant layers of security.
As an added precaution, deploy memory-protection schemes (such as non-executable stack/heap configuration and randomly mapped memory segments). This may complicate exploitation of memory-corruption vulnerabilities.
Microsoft has released a cumulative security update to address this issue. Reportedly, the fixes provided in MS06-013 may cause unintended breakage with certain ActiveX controls. Symantec has not confirmed this. Before deploying this patch in production environments, Users should thoroughly test the patch to ensure that it doesn't interfere with other software.
Heiko Schultze is credited with the discovery of this vulnerability.
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