Microsoft Outlook TNEF Stream With MAPI Attachment Remote Code Execution Vulnerability



Date Discovered

July 13, 2010


Microsoft Outlook is prone to a remote code-execution vulnerability because it fails to properly verify attachments. Attackers can exploit this issue by enticing an unsuspecting user into opening a specially crafted email attachment. Successfully exploiting this issue will allow an attacker to execute arbitrary code with the privileges of the currently logged-in user. Failed exploit attempts will result in a denial-of-service condition.

Technologies Affected

  • Microsoft Outlook 2002
  • Microsoft Outlook 2002 SP1
  • Microsoft Outlook 2002 SP2
  • Microsoft Outlook 2002 SP3
  • Microsoft Outlook 2003
  • Microsoft Outlook 2003 SP2
  • Microsoft Outlook 2003 SP3
  • Microsoft Outlook 2007
  • Microsoft Outlook 2007 SP1
  • Microsoft Outlook 2007 SP2


Block external access at the network boundary, unless external parties require service.
Filter access to the affected computer at the network boundary if global access isn't needed. Restricting access to only trusted computers and networks might greatly reduce the likelihood of a successful exploit.

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. This may indicate exploit attempts or activity that results from successful exploits.

Do not accept or execute files from untrusted or unknown sources.
Users should avoid accepting or opening unexpected files, especially if they originate from an untrusted or unfamiliar source.

When possible, limit the privileges granted to users to the least amount required.
To reduce the impact of latent vulnerabilities, limit user privileges to the least amount possible. This can help prevent privileged functions from running.

The vendor has released an advisory and fixes. Please see the references for more information.



Yorick Koster, working with the SSD/SecuriTeam Secure Disclosure program

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