Published:2011/06/15  Last Updated:2011/06/15

Microsoft Outlook read receipt function vulnerability


Microsoft Outlook contains a vulnerability in the read receipt function.

Products Affected

  • Microsoft Outlook 2003 Service Pack 3 and earlier
  • Microsoft Outlook 2007 Service Pack 1 and earlier


Microsoft Outlook contains a vulnerability in the read receipt function. A read receipt may be sent unintentionally, notifying the sender that the email was received.


A spam distributor may use this information to determine whether an email address is valid or not.


Upgrade the Software
Upgrade Outlook or apply a Service Pack according to the information provided by the developer.

Vendor Status

Vendor Status Last Update Vendor Notes
Microsoft Japan Co.,Ltd. vulnerable 2011/06/15


JPCERT/CC Addendum

This JVN publication was delayed to 2011/06/15 after the developer fix was developed. From the fiscal year 2011, JPCERT/CC is using a new vendor coordination procedure. This new procedure came from the recommendation of the fiscal year 2010 "Study Group on Information System Vulnerability Handling" aimed at more timely JVN publications.

Vulnerability Analysis by JPCERT/CC

Analyzed on 2011.06.15

Measures Conditions Severity
Access Required can be attacked over the Internet using packets
  • High
Authentication anonymous or no authentication (IP addresses do not count)
  • High
User Interaction Required the user must be convinced to take a standard action that does not feel harmful to most users, such as click on a link or view a file
  • Mid
Exploit Complexity some expertise and/or luck required (most buffer overflows, guessing correctly in small space, expertise in Windows function calls)
  • Mid-High

Description of each analysis measures


Ayako Kozakai of NTT DATA SECURITY CORPORATION reported this vulnerability to IPA.
JPCERT/CC coordinated with the developer under Information Security Early Warning Partnership.

Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
JVN iPedia JVNDB-2011-000040