Microsoft Outlook Mailto URI Remote Code Execution Vulnerability



Date Discovered

March 11, 2008


Microsoft Outlook is prone to a remote code-execution vulnerability because the application fails to adequately validate user-supplied data. Successfully exploiting this issue will allow attackers to execute arbitrary code with the privileges of the currently logged-in user. This will facilitate the remote compromise of affected computers.

Technologies Affected

  • Microsoft Outlook 2000 SP2
  • 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
  • Microsoft Outlook 2003 SP3
  • Microsoft Outlook 2007


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 includes but is not limited to requests that include NOP sleds and unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from successful exploits.

Do not follow links provided by unknown or untrusted sources.
Attackers could exploit this vulnerability by enticing a user to visit a malicious website. Do not follow links provided by sources of questionable integrity.

Implement multiple redundant layers of security.
Various memory-protection schemes (such as nonexecutable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.

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 to address this issue in supported versions of the affected application. Please see the referenced advisory for details on obtaining and applying the appropriate updates.



Greg MacManus of VeriSign iDefense Labs is credited with the discovery of this vulnerability.

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