January 10, 2006
Microsoft Windows is susceptible to a remotely exploitable buffer-overflow vulnerability. This issue is due to the software's failure to properly bounds-check user-supplied input before copying it to an insufficiently sized memory buffer.
This issue allows remote attackers to execute arbitrary machine code in the context of the vulnerable software on the targeted user's computer.
Do not accept communications that originate from unknown or untrusted sources.
Do not follow links or open email from unknown or untrusted sources.
Implement multiple redundant layers of security.
An attacker's ability to exploit this vulnerability to execute arbitrary code may be hindered through the use of various memory-protection schemes. Where possible, use non-executable and randomly mapped memory segments.
Modify default configuration files to disable any unwanted behavior.
Since exploitation requires users to view HTML content, consider disabling HTML rendering in email clients to mitigate the possibility of remote exploitation. Note that disabling HTML content in email clients may reduce their functionality.
Run all software as a nonprivileged user with minimal access rights.
Always run non-administrative software as a non-administrative user with the minimal amount of privileges required to successfully operate. This will limit the potential damage that successful exploitation may achieve.
Avaya security advisory ASA-2006-004 addresses this issue. Avaya recommends following Microsoft's instructions for installing the Operating System patch.
Nortel has released an advisory (2006006582) to identify vulnerable products. The vendor advises customers to follow Microsoft's recommendations and install fixes supplied by Microsoft.
Fixes are available:
Fang Xing is credited with the discovery of this issue.
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