CVE-2008-4822 in Flash Player
Summary
by MITRE
Adobe Flash Player 9.0.124.0 and earlier does not properly interpret policy files, which allows remote attackers to bypass a non-root domain policy.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/20/2019
Adobe Flash Player versions 9.0.124.0 and earlier contain a critical vulnerability in their handling of cross-domain policy files that fundamentally undermines the security model designed to prevent unauthorized access between domains. This flaw exists within the player's interpretation of policy files that should enforce strict boundaries between different web domains, allowing malicious actors to circumvent these protections through improper handling of policy file parsing.
The technical implementation of this vulnerability stems from insufficient validation of policy file contents within the Flash Player's security architecture. When Flash Player processes cross-domain policy files, it fails to properly validate the structure and content of these files, particularly in how it interprets the policy file format and the specific domains that are permitted to access resources. This improper interpretation creates a window where attackers can craft malicious policy files or manipulate existing ones to grant unauthorized access to resources that should be protected by domain restrictions.
The operational impact of this vulnerability is severe as it enables remote attackers to bypass domain-based security restrictions that are fundamental to preventing cross-site scripting attacks and unauthorized data access. An attacker could potentially exploit this weakness to access resources on different domains that should be protected by Flash Player's security policies, leading to potential data exfiltration, privilege escalation, or further exploitation of other vulnerabilities within the target environment. This vulnerability directly violates the core security principle of domain isolation that Flash Player relies upon for protecting users from malicious content.
This vulnerability maps directly to CWE-284 Access Control Bypass and aligns with ATT&CK technique T1211 Lateral Movement through the ability to bypass security controls that should prevent unauthorized access between domains. The flaw represents a failure in the security model's enforcement mechanism, where the policy file interpretation process does not properly validate domain boundaries, creating a path for attackers to gain unauthorized access to resources that should be protected by the cross-domain policy enforcement system. Organizations using affected Flash Player versions face significant risk of unauthorized access to sensitive resources and potential compromise of user data. The vulnerability demonstrates the critical importance of proper policy file validation in security-critical applications and highlights the potential for even minor implementation flaws to create major security weaknesses in complex security architectures.
Mitigation strategies should focus on immediate patching of affected Flash Player versions, implementation of network-level controls to restrict Flash content execution, and deployment of additional security measures such as content security policies and web application firewalls to provide defense-in-depth. Organizations should also consider implementing monitoring for suspicious cross-domain requests and policy file access patterns that might indicate exploitation attempts. Given the nature of this vulnerability, it is essential to ensure that all Flash Player installations are updated to versions that properly implement policy file validation and enforcement mechanisms.