CVE-2007-0768 in Yahoo!
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the Contact Details functionality in Yahoo! Messenger 8.1.0.209 and earlier allow user-assisted remote attackers to inject arbitrary web script or HTML via a javascript: URI in the SRC attribute of an IMG element to the (1) First Name, (2) Last Name, and (3) Nickname fields. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 08/04/2019
The vulnerability identified as CVE-2007-0768 represents a critical cross-site scripting flaw within Yahoo! Messenger version 8.1.0.209 and earlier releases. This security weakness specifically targets the Contact Details functionality of the messaging application, creating a pathway for malicious actors to execute arbitrary web scripts within the context of a victim's browser session. The vulnerability operates through a user-assisted attack vector, meaning that an attacker must convince a user to interact with a specially crafted malicious contact entry to exploit the flaw effectively.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the contact management system of Yahoo! Messenger. When users enter contact information including first name, last name, and nickname fields, the application fails to properly sanitize or escape special characters in these input fields. Attackers can exploit this by injecting javascript: URIs within the src attribute of IMG elements, which are then rendered in the contact details display. This particular method leverages the IMG tag's src attribute to execute malicious javascript code through the javascript: protocol, bypassing traditional input filtering mechanisms that might only check for standard HTML tags.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal cookies, redirect users to malicious websites, or even execute more sophisticated attacks through the compromised Messenger client. The user-assisted nature of the attack requires social engineering elements where an attacker must convince a victim to add or view a malicious contact entry, but once executed, the vulnerability can persist across multiple sessions and potentially compromise the user's entire communication environment. This weakness particularly affects users who frequently interact with contacts from untrusted sources or who may be targeted through spear-phishing campaigns.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-79: Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly sanitize user input before incorporating it into web pages. The ATT&CK framework categorizes this under T1566: Phishing and T1059: Command and Scripting Interpreter, as it enables both social engineering attacks and malicious code execution. The vulnerability also aligns with the OWASP Top Ten 2004 category A03: Cross-Site Scripting (XSS) which was later updated to A07: Identification and Authentication Failures in the 2017 version, demonstrating the persistent nature of XSS threats in web and client applications.
Mitigation strategies for this vulnerability should include immediate patching of Yahoo! Messenger to version 8.1.0.210 or later, which contains the necessary input sanitization fixes. Users should also implement additional security measures such as disabling automatic contact addition from unknown sources, regularly reviewing contact lists for suspicious entries, and employing browser-based XSS protection mechanisms. Organizations should consider implementing network-based intrusion detection systems that can identify and block malicious javascript content in instant messaging traffic. The vulnerability underscores the importance of input validation at multiple layers of application architecture and demonstrates how seemingly simple user interface elements can become attack vectors when proper security controls are not implemented.