CVE-2018-4919 in Flash Player
Summary
by MITRE
Adobe Flash Player versions 28.0.0.161 and earlier have an exploitable use after free vulnerability. Successful exploitation could lead to arbitrary code execution in the context of the current user.
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Analysis
by VulDB Data Team • 02/05/2021
Adobe Flash Player contains a critical use after free vulnerability in its memory management system that affects versions 28.0.0.161 and earlier. This flaw resides in the way the player handles memory deallocation and subsequent reuse of objects, creating a scenario where an attacker can manipulate freed memory regions to execute malicious code. The vulnerability stems from insufficient bounds checking and improper memory management practices within the Flash Player runtime environment, specifically in how it processes certain multimedia objects and handles object references.
The technical exploitation of this use after free vulnerability occurs when a malicious Flash content attempts to access memory that has already been freed by the application's memory manager. Attackers can craft specially designed SWF files that trigger the vulnerable code path, causing the Flash Player to free a memory object while maintaining references to it. When the application subsequently attempts to access this freed memory, an attacker can overwrite the memory contents with malicious payload data, leading to arbitrary code execution. This type of vulnerability is particularly dangerous because it allows for privilege escalation and can be exploited in web browser contexts where the Flash Player runs with the user's privileges.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise in many scenarios. When successfully exploited, the malicious code can bypass security restrictions, access sensitive user data, install persistent backdoors, or establish command and control channels. The vulnerability affects all operating systems where Adobe Flash Player is installed, including windows macos and linux platforms, making it a widespread concern for enterprise environments. Organizations that continue to support legacy Flash content face significant risk exposure, as this vulnerability can be leveraged through drive-by downloads from compromised websites or malicious email attachments containing embedded Flash content.
Mitigation strategies for this vulnerability require immediate action including disabling Flash Player functionality across all systems and updating to patched versions of Adobe Flash Player. Security teams should implement network-level controls to block Flash content delivery and monitor for suspicious Flash-related network traffic patterns. The vulnerability aligns with CWE-416 which specifically addresses use after free conditions in software applications, and represents a common vector for exploitation in the ATT&CK framework under the initial access and execution phases. Organizations should also consider implementing application whitelisting policies to prevent Flash Player from running in production environments and conduct thorough security assessments of any remaining Flash content in their infrastructure. Given the end of Adobe Flash Player support in 2020, organizations should prioritize complete migration away from Flash-based applications to eliminate this and similar legacy vulnerabilities from their attack surface.