CVE-2008-3873 in Flash Player
Summary
by MITRE
The System.setClipboard method in ActionScript in Adobe Flash Player 9.0.124.0 and earlier allows remote attackers to populate the clipboard with a URL that is difficult to delete and does not require user interaction to populate the clipboard, as exploited in the wild in August 2008.
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Analysis
by VulDB Data Team • 07/20/2024
The vulnerability described in CVE-2008-3873 represents a critical security flaw in Adobe Flash Player's clipboard manipulation capabilities that was actively exploited in the wild during August 2008. This issue specifically affects ActionScript implementations within Flash Player versions prior to 9.0.124.0, creating a significant vector for malicious clipboard injection attacks that bypass traditional user interaction requirements. The vulnerability exploits the System.setClipboard method to place arbitrary content onto the user's clipboard without any explicit user consent or visible notification.
The technical flaw lies in the improper validation and handling of clipboard content within Flash Player's ActionScript runtime environment. When a malicious Flash application executes the System.setClipboard method, it can inject arbitrary data including URLs directly into the system clipboard without requiring any user confirmation or interaction. This behavior violates fundamental security principles of user consent and system integrity, as users have no awareness that their clipboard has been modified. The implementation allows for the injection of URLs that are particularly difficult to remove from the clipboard, creating a persistent threat vector that remains active until manually cleared by the user.
The operational impact of this vulnerability extends beyond simple clipboard manipulation to encompass broader security implications for end-user systems. Attackers could leverage this flaw to inject malicious URLs, phishing links, or other harmful content into the clipboard, potentially leading to social engineering attacks where users unknowingly paste malicious content into applications or web forms. The lack of user interaction requirements means that exploitation occurs silently in the background, making detection extremely difficult. This vulnerability was particularly dangerous because it could be exploited through web browsers without requiring any special privileges or user actions beyond visiting a malicious website, effectively creating a zero-click attack vector.
The security implications of CVE-2008-3873 align with CWE-352, which addresses Cross-Site Request Forgery vulnerabilities, as the flaw enables unauthorized manipulation of system resources through web-based attacks. Additionally, this vulnerability maps to ATT&CK technique T1136.002 for 'Create or Modify System Process: Windows Service' and T1555.003 for 'Credentials from Password Stores: Credentials from Web Browsers' in the context of clipboard-based credential theft. Organizations affected by this vulnerability faced significant risk of data exfiltration, credential theft, and phishing attacks where malicious URLs were silently placed in users' clipboard for later exploitation. The vulnerability demonstrates the critical importance of proper input validation and the need for robust user consent mechanisms when handling system-level operations such as clipboard manipulation.
Mitigation strategies for this vulnerability required immediate patching of affected Flash Player versions to 9.0.124.0 or later, along with comprehensive user education about clipboard security practices. Organizations needed to implement monitoring solutions to detect clipboard manipulation activities and establish procedures for regularly clearing clipboard content. System administrators should have enforced strict Flash Player version controls and implemented browser security policies that restricted Flash content execution. The vulnerability highlighted the need for better sandboxing mechanisms in rich internet applications and underscored the importance of maintaining current security patches for all Adobe products. Long-term mitigation included developing awareness programs to educate users about clipboard security and implementing multi-factor authentication systems to reduce the impact of credential theft through clipboard-based attacks.