CVE-2008-3872 in Flash Player
Summary
by MITRE
Adobe Flash Player 8.0.39.0 and earlier, and 9.x up to 9.0.115.0, allows remote attackers to bypass the allowScriptAccess parameter setting via a crafted SWF file with unspecified "Filter evasion" manipulations.
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Analysis
by VulDB Data Team • 08/02/2021
Adobe Flash Player versions 8.0.39.0 and earlier, as well as version 9.x up to 9.0.115.0, contain a critical security vulnerability that enables remote attackers to circumvent the allowScriptAccess parameter protection mechanism. This vulnerability stems from unspecified filter evasion manipulations within the SWF file processing logic, allowing malicious actors to bypass intended security restrictions that should prevent cross-site scripting attacks. The flaw specifically targets the allowScriptAccess parameter which is designed to control whether Flash content can access external scripts and data from different domains, creating a potential pathway for unauthorized code execution and data exfiltration.
The technical implementation of this vulnerability involves sophisticated manipulation of SWF file structures that exploit weaknesses in the Flash Player's parsing and validation mechanisms. Attackers can craft malicious SWF files that contain filter evasion techniques designed to bypass the normal parameter validation checks that should enforce the allowScriptAccess restrictions. These manipulations leverage the way Flash Player processes and interprets various file components, particularly those related to cross-domain policy enforcement and script access controls. The vulnerability operates at the application layer and represents a direct violation of the security model that Flash Player implements to protect users from malicious content. According to CWE classification, this vulnerability maps to CWE-284, which deals with improper access control, and specifically addresses weaknesses in the implementation of access control mechanisms.
The operational impact of this vulnerability is severe and far-reaching, as it allows attackers to execute arbitrary code on victim systems without proper authorization. When exploited, the vulnerability can enable attackers to bypass security restrictions that are fundamental to preventing cross-site scripting attacks, potentially leading to complete system compromise. Users who view malicious Flash content may unknowingly grant unauthorized script access to remote attackers, creating opportunities for data theft, privilege escalation, and further network infiltration. The vulnerability affects a wide range of Flash Player versions and can be exploited through various attack vectors including web browsers, email attachments, and malicious websites. This type of vulnerability directly aligns with ATT&CK technique T1059, which involves executing malicious code through legitimate system processes, and T1071, which focuses on application layer protocol usage for command and control communications.
Mitigation strategies for this vulnerability require immediate patching of affected Flash Player versions to the latest available releases that contain the necessary security fixes. Organizations should implement comprehensive monitoring of Flash content usage and consider disabling Flash Player entirely where possible, as the platform has been deprecated and poses ongoing security risks. Network administrators should deploy intrusion detection systems capable of identifying suspicious SWF file patterns and filter traffic containing potentially malicious Flash content. Additionally, browser security policies should be configured to restrict Flash content execution and implement strict content security policies that prevent cross-domain script access. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of vulnerable Flash Player installations within the organization's infrastructure, as the vulnerability represents a persistent threat that could be exploited for extended periods if not properly addressed.