Quiksoft EasyMail SMTP ActiveX control stack buffer overflow vulnerabilities

ID VU:281977
Type cert
Reporter CERT
Modified 2007-08-30T00:00:00



The Quiksoft EasyMail SMTP ActiveX control contains multiple stack buffer overflow vulnerabilities, which could allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.


Quiksoft EasyMail Objects is a set of ActiveX controls that provides email functionality, including SMTP, POP3, and IMAP4. The EasyMail SMTP ActiveX control, which is provided by emsmtp.dll, contains multiple stack buffer overflow vulnerabilities.

This control is bundled with several applications, including Earthlink internet access software. Exploit code for this vulnerability is publicly available.


A remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system with privileges of the user.


We are currently unaware of a practical solution to this problem. Please consider the following workarounds

Disable the Quiksoft EasyMail ActiveX control in Internet Explorer

The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:

More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{68AC0D5F-0424-11D5-822F-00C04F6BA8D9}]
"Compatibility Flags"=dword:00000400
Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document.

Systems Affected

Vendor| Status| Date Notified| Date Updated
Earthlink| | 16 Apr 2007| 29 Aug 2007
Gate Comm Software| | -| 29 Aug 2007
Quiksoft| | 08 Feb 2007| 29 Aug 2007
If you are a vendor and your product is affected, let us know.

CVSS Metrics

Group | Score | Vector
Base | N/A | N/A
Temporal | N/A | N/A
Environmental | N/A | N/A


  • <http://www.cert.org/tech_tips/securing_browser/#Internet_Explorer>
  • <http://www.quicksoftcorp.com/objects/>
  • <http://www.quicksoftcorp.com/clients/whouses.asp>


This vulnerability was reported by Will Dormann of the CERT/CC. The vulnerability was also independently discovered and publicly disclosed by rgod.

This document was written by Will Dormann.

Other Information

  • CVE IDs: Unknown
  • Date Public: 27 Aug 2007
  • Date First Published: 29 Aug 2007
  • Date Last Updated: 30 Aug 2007
  • Severity Metric: 25.82
  • Document Revision: 5