CVE-2018-4920 in Flash Player
Summary
by MITRE
Adobe Flash Player versions 28.0.0.161 and earlier have an exploitable type confusion 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 type confusion vulnerability that arises from improper handling of object types during runtime execution. This flaw exists in versions 28.0.0.161 and earlier, where the player fails to properly validate type information when processing maliciously crafted flash content. The vulnerability stems from the player's inability to distinguish between different object types, allowing an attacker to manipulate memory structures and execute arbitrary code within the context of the currently logged-in user. This type confusion issue represents a fundamental flaw in the player's memory management and object handling mechanisms, creating a pathway for privilege escalation and persistent system compromise. The vulnerability is particularly dangerous because it can be triggered through web browsers that have Flash Player installed, making it accessible to attackers who can deliver malicious content via compromised websites or phishing campaigns.
The technical exploitation of this vulnerability involves crafting specially formatted flash content that causes the player to misinterpret object types during runtime operations. When Flash Player processes such content, it attempts to perform operations on objects using incorrect type assumptions, leading to memory corruption and potential code execution. This type confusion typically occurs in scenarios where the player's internal type system fails to maintain proper type safety during dynamic object manipulation or when handling complex data structures. The flaw can be leveraged to bypass security restrictions and execute malicious code with the privileges of the current user, potentially leading to full system compromise. According to the CWE database, this vulnerability maps to CWE-476 which describes NULL pointer dereference, though the specific manifestation in Flash Player creates a more complex type confusion scenario. The attack surface is broad as it affects all systems running vulnerable Flash Player versions and can be delivered through standard web browsing activities, making it particularly dangerous for enterprise environments where users may encounter malicious content without proper security controls.
The operational impact of CVE-2018-4920 extends beyond simple code execution to encompass complete system compromise and data exfiltration capabilities. Successful exploitation allows attackers to establish persistent access, install additional malware, and potentially escalate privileges to administrative levels. The vulnerability's presence in widely deployed Flash Player versions means that organizations with legacy systems or users who have not updated their software remain at significant risk. Attackers can leverage this vulnerability to create backdoors, harvest sensitive information, or use the compromised system as a launch point for further attacks within a network. The threat landscape for this vulnerability includes both automated exploit kits and targeted attacks from advanced persistent threat groups. Organizations that rely on Flash content for business operations face particular risk, as the vulnerability can be exploited through legitimate business processes that require Flash Player functionality. The attack vector through web browsers means that simple user interaction with malicious websites can result in system compromise, making user education and patch management critical defensive measures. This vulnerability also demonstrates the challenges of maintaining security for legacy software platforms and the importance of proper software lifecycle management.
Mitigation strategies for CVE-2018-4920 primarily focus on immediate remediation through patching and software updates. Adobe strongly recommends that all users upgrade to Flash Player version 28.0.0.162 or later, which contains the necessary fixes to address the type confusion vulnerability. Organizations should implement comprehensive patch management policies that ensure all systems running Flash Player are updated promptly. Additionally, security controls such as disabling Flash Player in web browsers, implementing content filtering solutions, and using sandboxing technologies can provide additional layers of protection. Network-based defenses including web application firewalls and intrusion detection systems can help identify and block exploitation attempts. Regular security assessments should be conducted to identify systems running vulnerable versions of Flash Player, particularly in legacy environments where updates may be delayed. According to ATT&CK framework, this vulnerability aligns with techniques such as T1059.007 for command and script interpreter and T1068 for exploit for privilege escalation. Organizations should also consider implementing user behavior analytics and endpoint detection solutions to identify anomalous activities that may indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date security patches and the risks associated with running unsupported software versions in enterprise environments.