CVE-2007-0519 in U2U Instant Messenger
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in memcp.php in XMB U2U Instant Messenger allows remote authenticated users to inject arbitrary web script or HTML via the recipient field.
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Analysis
by VulDB Data Team • 10/07/2017
The CVE-2007-0519 vulnerability represents a classic cross-site scripting flaw within the XMB U2U Instant Messenger application's memcp.php component. This security weakness specifically targets the recipient field parameter processing, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of other users' browsers. The vulnerability affects authenticated users who possess valid credentials to access the messaging system, making it particularly concerning for environments where user authentication is required to utilize the instant messaging functionality. The flaw stems from inadequate input validation and output sanitization mechanisms that fail to properly escape or filter user-supplied data before it is rendered back to the browser.
The technical exploitation of this vulnerability occurs when an authenticated attacker crafts malicious input containing script tags or HTML elements within the recipient field of a message. When the vulnerable application processes this input and displays it in the user interface, the embedded malicious code executes in the browser context of other users who view the affected message. This type of attack falls under the CWE-79 category of Cross-Site Scripting, specifically representing a reflected XSS vulnerability where the malicious payload is reflected off the web server back to the user's browser. The attack vector requires the user to be authenticated to the system, which means the attacker must first obtain valid credentials or exploit another vulnerability to gain access to the authenticated session.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, redirection to malicious websites, and data exfiltration. An attacker could craft messages that steal session cookies from unsuspecting users, effectively allowing them to impersonate those users and gain unauthorized access to their messaging accounts. The vulnerability also permits the execution of persistent XSS attacks if the malicious content is stored and displayed across multiple sessions, potentially affecting numerous users over time. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing: Spearphishing Attachment) and T1531 (Account Access Removal) as it enables unauthorized access to user accounts and can be used to establish persistent access through stolen session tokens.
Mitigation strategies for CVE-2007-0519 should focus on implementing robust input validation and output encoding mechanisms throughout the application's data processing pipeline. The most effective approach involves sanitizing all user-supplied input, particularly fields that are later rendered in web interfaces, by implementing proper HTML entity encoding or using secure output escaping techniques. Organizations should also consider implementing Content Security Policy (CSP) headers to limit the execution of unauthorized scripts within the application context. Additionally, the application should enforce strict validation of recipient field inputs to reject potentially malicious content and implement proper session management controls to detect and prevent session hijacking attempts. Regular security code reviews and penetration testing should be conducted to identify similar vulnerabilities in other application components, as this type of flaw often indicates broader input validation weaknesses that may exist elsewhere in the system architecture.