Microsoft Outlook Malformed Email Header Remote Denial of Service Vulnerability



Date Discovered

January 9, 2007


Microsoft Outlook is prone to a remote denial-of-service vulnerability because the application fails to properly handle malformed email messages. A remote attacker can exploit this issue to crash affected email clients. This issue will persist as long as the email message resides on the mail server, creating a prolonged denial-of-service condition.

Technologies Affected

  • Microsoft Office 2000
  • Microsoft Office 2000 SP1
  • Microsoft Office 2000 SP2
  • Microsoft Office 2000 SP3
  • Microsoft Office 2003
  • Microsoft Office 2003 SP1
  • Microsoft Office 2003 SP2
  • Microsoft Office XP
  • Microsoft Office XP SP1
  • Microsoft Office XP SP2
  • Microsoft Office XP SP3
  • Microsoft Outlook 2000 SP2
  • Microsoft Outlook 2000 SR1
  • Microsoft Outlook 2000
  • Microsoft Outlook 2000 SP3
  • Microsoft Outlook 2002
  • Microsoft Outlook 2002 SP1
  • Microsoft Outlook 2002 SP2
  • Microsoft Outlook 2002 SP3
  • Microsoft Outlook 2003
  • Microsoft Outlook 2003 SP2


Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity. Monitor logs regularly for any signs of unusual activity, such as repeated crashes.

Do not open email messages from unknown or untrusted individuals.
Users should never trust incoming email messages originating from unknown or untrusted sources.

Microsoft has released an advisory and fixes to address this issue. Please see the references for more information.



The vendor disclosed this issue.

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