CVE-2008-4401 in Flash Player
Summary
by MITRE
ActionScript in Adobe Flash Player 9.0.124.0 and earlier does not require user interaction in conjunction with (1) the FileReference.browse operation in the FileReference upload API or (2) the FileReference.download operation in the FileReference download API, which allows remote attackers to create a browse dialog box, and possibly have unspecified other impact, via an SWF file.
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Analysis
by VulDB Data Team • 08/02/2021
Adobe Flash Player versions 9.0.124.0 and earlier contain a critical security flaw in their ActionScript implementation that fundamentally undermines user consent mechanisms for file operations. This vulnerability specifically affects the FileReference API which handles file browsing and download operations within Flash applications. The flaw occurs because the Flash Player fails to enforce mandatory user interaction requirements when executing FileReference.browse and FileReference.download operations, creating a dangerous scenario where malicious SWF files can programmatically trigger file dialog boxes without explicit user approval.
The technical nature of this vulnerability stems from the improper implementation of security boundaries within the Flash Player's ActionScript runtime environment. When a malicious SWF file executes FileReference.browse or FileReference.download operations, the system should require explicit user confirmation before allowing any file system interaction. However, due to this flaw, these operations can be initiated automatically, bypassing the expected user consent process that normally prevents unauthorized file access. This creates a situation where attackers can potentially force users into file selection dialogs, potentially leading to unintended file uploads or downloads without user awareness.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it represents a fundamental breakdown in browser security models that Flash Player was designed to enforce. Attackers can craft malicious SWF files that automatically open browse dialogs, potentially tricking users into selecting files they might not otherwise choose, or forcing downloads of malicious content. The unspecified other impacts mentioned in the CVE description suggest that this flaw could enable additional attack vectors including privilege escalation, data exfiltration, or exploitation of other system components that rely on proper user consent mechanisms. This vulnerability particularly affects web applications that use Flash-based file handling features, making it a significant concern for organizations relying on Flash-based content delivery.
From a cybersecurity perspective, this vulnerability aligns with CWE-613, which addresses insufficient session management, and represents a clear violation of the principle of least privilege in user consent enforcement. The ATT&CK framework would categorize this as a privilege escalation technique through application sandbox bypass, as it allows attackers to circumvent the normal security boundaries that protect user file systems. Organizations should immediately implement mitigation strategies including disabling Flash Player plugins in web browsers, updating to patched versions of Flash Player, and implementing network-level controls to prevent execution of potentially malicious SWF files. The vulnerability also highlights the importance of proper API design and the necessity of enforcing mandatory user interaction requirements for all file system operations, regardless of the application layer involved.
This flaw demonstrates the critical importance of maintaining proper security boundaries in rich internet applications and the potential for seemingly minor API implementation issues to create significant security risks. The vulnerability essentially removes the user's ability to make informed decisions about file system access, which represents a fundamental breach of user security expectations. Given the widespread use of Flash Player in web applications at the time of this vulnerability's discovery, the impact was substantial and required immediate attention from security professionals across all affected organizations.