March 14, 2006
Microsoft Excel is prone to a remote code-execution vulnerability. This issue may be triggered when an Excel document with a malformed formula size is opened.
- Avaya Modular Messaging (MAS) 3.0.0
- 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 2004 for Mac
- Microsoft Excel Viewer 2003
- Microsoft Excel x for Mac
- Nortel Networks Enterprise Network Management System
- Nortel Networks IP softphone 2050
- Nortel Networks MCS 5100 3.0.0
- Nortel Networks MCS 5200 3.0.0
- Nortel Networks Optivity Telephony Manager (OTM)
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 exploitation of memory-corruption vulnerabilities.
Microsoft has released fixes to address this vulnerability in supported versions of the affected software. Avaya has released advisory ASA-2006-069 to identify vulnerable Avaya products. Avaya advises customers to apply patches released by Microsoft. Please see references for more information.
Discovery is credited to Dejun Meng of the Fortinet Security Response Team.
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