CVE-2008-5697 in Extension For Firefox
Summary
by MITRE
The skype_tool.copy_num method in the Skype extension BETA 2.2.0.95 for Firefox allows remote attackers to write arbitrary data to the clipboard via a string argument.
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Analysis
by VulDB Data Team • 11/06/2024
The vulnerability identified as CVE-2008-5697 resides within the Skype extension for Firefox, specifically in the skype_tool.copy_num method implementation. This flaw represents a classic clipboard manipulation vulnerability that emerged during the era of browser-based communication tools and extensions. The Skype extension BETA 2.2.0.95 introduced functionality to copy phone numbers directly from web pages into the system clipboard, but this feature was implemented without proper input validation or sanitization measures. The method accepts a string argument that is then written to the clipboard without any restrictions on the content or length of the data being copied.
The technical nature of this vulnerability stems from the extension's failure to validate user input before executing clipboard operations. When a malicious actor crafts a specially crafted string argument, the skype_tool.copy_num method processes this input and writes it directly to the system clipboard without sanitization. This creates a potential vector for malicious data injection where attackers can place arbitrary content into the clipboard that may later be pasted by unsuspecting users. The vulnerability operates at the intersection of browser extension security and clipboard manipulation, where the extension's elevated privileges allow it to interact with system-level clipboard functionality. This type of vulnerability aligns with CWE-170, which addresses improper handling of string termination or encoding, and CWE-20, which covers input validation issues.
The operational impact of this vulnerability extends beyond simple clipboard manipulation as it can be leveraged in various social engineering attacks. An attacker could craft malicious strings that appear legitimate but contain hidden malicious content such as URLs, executable code, or phishing indicators. When users paste clipboard contents into applications, the malicious data could execute unintended operations or lead to further compromise. The vulnerability particularly affects users who frequently use the Skype extension for phone number copying, as the attack surface is expanded through normal browsing activities. This type of vulnerability is categorized under ATT&CK technique T1552.001 for unsecured credentials and T1133 for external remote services, as it enables attackers to manipulate user clipboard data in ways that could facilitate credential theft or phishing attacks.
Mitigation strategies for this vulnerability require immediate patching of the affected Skype extension to version 2.2.1.0 or later, which includes proper input validation for the copy_num method. Users should disable or uninstall the vulnerable extension until a secure version is deployed. Organizations should implement browser extension management policies that restrict installation of unsigned or untrusted extensions. The fix involves implementing proper string validation and sanitization before clipboard operations, ensuring that input arguments are checked for malicious content and length restrictions are enforced. Security monitoring should include detection of unusual clipboard activity patterns that may indicate exploitation attempts. Additionally, user education regarding clipboard security practices and the risks of pasting unknown content from clipboard data can help reduce the impact of such vulnerabilities in operational environments.