Executive Summary

Title Yahoo! Webcam image upload ActiveX control vulnerable to arbitrary code execution
Name VU#949817 First vendor Publication 2007-06-08
Vendor VU-CERT Last vendor Modification 2007-06-11
Severity (Vendor) N/A Revision M

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:M/Au:N/C:C/I:C/A:C)
Cvss Base Score 9.3 Attack Range Network
Cvss Impact Score 10 Attack Complexity Medium
Cvss Expoit Score 8.6 Authentication None Required
Calculate full CVSS 2.0 Vectors scores


Vulnerability Note VU#949817

Yahoo! Webcam image upload ActiveX control vulnerable to arbitrary code execution


The Yahoo! Webcam image upload ActiveX control contains a stack buffer overflow, which can allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

I. Description

Yahoo! Webcam is a component of Yahoo! Messenger that allows users to chat via webcams over a network. Yahoo! Webcam Upload includes an ActiveX control provided by the file ywcupl.dll . This ActiveX control contains a stack buffer overflow vulnerability in the Server property.

We are aware of publicly available exploit code for this vulnerability.

II. Impact

By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker may be able to execute arbitrary code with the privileges of the user. The attacker could also cause Internet Explorer (or the program using the WebBrowser control) to crash.

III. Solution

Apply an update

This issue is addressed in Yahoo! Messenger 8.1. If you are unable to upgrade, please consider the following workarounds:

Disable the Yahoo! Messenger 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_MACHINESOFTWAREMicrosoftInternet ExplorerActiveX Compatibility{DCE2F8B1-A520-11D4-8FD0-00D0B7730277}]
    "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

VendorStatusDate Updated
Yahoo, Inc.Vulnerable8-Jun-2007




This issue was reported by eEye Digital Security in EEYEZD-20070606.

This document was written by Chris Taschner.

Other Information

Date Public06/07/2007
Date First Published06/08/2007 11:58:12 AM
Date Last Updated06/11/2007
CERT Advisory 
CVE Name 
Document Revision20

Original Source

Url : http://www.kb.cert.org/vuls/id/949817

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-119 Failure to Constrain Operations within the Bounds of a Memory Buffer

CPE : Common Platform Enumeration

Application 6

Open Source Vulnerability Database (OSVDB)

Id Description
37082 Yahoo! Webcam Upload ActiveX (ywcupl.dll) send Method Overflow

A buffer overflow exists in Yahoo! Messenger. The Webcam Upload ActiveX control fails to validate data passed to the 'send' method resulting in a stack overflow. With a specially crafted website, a context-dependent attacker can cause arbitrary code execution resulting in a loss of integrity.

Snort® IPS/IDS

Date Description
2014-01-10 Yahoo Webcam Upload ActiveX function call unicode access
RuleID : 11825 - Revision : 11 - Type : BROWSER-PLUGINS
2014-01-10 Yahoo Webcam Upload ActiveX function call access
RuleID : 11824 - Revision : 11 - Type : BROWSER-PLUGINS
2014-01-10 Yahoo Webcam Upload ActiveX clsid unicode access
RuleID : 11823 - Revision : 11 - Type : BROWSER-PLUGINS
2014-01-10 Yahoo Webcam Upload ActiveX clsid access
RuleID : 11822 - Revision : 14 - Type : BROWSER-PLUGINS

Nessus® Vulnerability Scanner

Date Description
2007-06-11 Name : The remote Windows host has a least one ActiveX control that is affected by a...
File : yahoo_msgr_webcam_activex_buffer_overflows.nasl - Type : ACT_GATHER_INFO