July 10, 2006
Microsoft Excel is prone to a remote code-execution vulnerability. A remote attacker may exploit this issue to execute arbitrary machine code in the context of the user running the application. Note that Microsoft Office applications include functionality to embed Office files as objects contained in other Office files. As an example, Word files may contain embedded malicious Excel files, making Word documents another possible attack vector.
- Microsoft Excel 2000
- Microsoft Excel 2000 SP2
- Microsoft Excel 2000 SP3
- Microsoft Excel 2000 SR1
- Microsoft Excel 2002
- Microsoft Excel 2002 SP1
- Microsoft Excel 2002 SP2
- Microsoft Excel 2002 SP3
- Microsoft Excel 2003
- Microsoft Excel 2003 SP1
- Microsoft Excel 2003 SP2
- Microsoft Excel 2004 for Mac
- Microsoft Excel Viewer 2003
- Microsoft Excel x for Mac
- Microsoft Office 2000 SP3
- Microsoft Office 2003 SP1
- Microsoft Office 2003 SP2
- Microsoft Office 2004 for Mac
- Microsoft Office XP SP3
- Microsoft Office v. X
- Microsoft Works Suite 2004
- Microsoft Works Suite 2005
- Microsoft Works Suite 2006
Run all software as a nonprivileged user with minimal access rights.
All non-administrative tasks should be performed as an unprivileged user with minimal access rights.
Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of suspicious or anomalous activity. This may help detect malicious actions that an attacker may take after successfully exploiting vulnerabilities in applications. Review all applicable logs regularly.
Do not accept or execute files from untrusted or unknown sources.
Users should never accept files from untrusted or unknown sources, because they may be malicious in nature. Avoid opening email attachments from unknown or questionable sources.
Do not follow links provided by unknown or untrusted sources.
Users should avoid websites of questionable integrity. Never follow links supplied by unknown or untrusted sources.
Implement multiple redundant layers of security.
Since this issue may be leveraged to execute code, we recommend memory-protection schemes, such as non-executable stack/heap configurations and randomly mapped memory segments. This tactic may complicate exploits of memory-corruption vulnerabilities.
Microsoft has released an advisory and fixes to address this issue. Please see the references for more information.
Manuel Santamarina Suarez is credited with discovering this issue.
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