CVE-2016-4223 in Flash Player
Summary
by MITRE • 01/26/2023
Adobe Flash Player before 18.0.0.366 and 19.x through 22.x before 22.0.0.209 on Windows and OS X and before 11.2.202.632 on Linux allows attackers to execute arbitrary code by leveraging an unspecified "type confusion," a different vulnerability than CVE-2016-4224 and CVE-2016-4225.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/26/2023
Adobe Flash Player versions prior to 18.0.0.366 and 19.x through 22.x before 22.0.0.209 on Windows and OS X platforms, along with versions before 11.2.202.632 on Linux systems, contained a critical type confusion vulnerability that enabled remote code execution. This flaw represented a distinct security issue separate from CVE-2016-4224 and CVE-2016-4225, indicating multiple vulnerabilities within the same software component. The vulnerability stemmed from improper handling of data types during runtime execution, where the Flash Player's ActionScript virtual machine failed to properly validate or manage object type information. This type confusion occurred when the application attempted to use an object as if it were of one type while it was actually of another, creating a scenario where attackers could manipulate memory layout and execute arbitrary code. The vulnerability was particularly dangerous because it allowed remote attackers to craft malicious Flash content that would trigger the type confusion during normal playback operations, bypassing standard security mechanisms. According to the CWE classification, this represents a CWE-476: NULL Pointer Dereference vulnerability that manifests through type confusion patterns, where the software's type system fails to properly enforce type safety. The attack vector typically involved delivering malicious SWF files through web browsers or email attachments, with the exploitation occurring when users opened the compromised content. The operational impact was severe as victims could be compromised without any user interaction beyond viewing the malicious content, making it particularly effective for drive-by download attacks. The vulnerability exploited fundamental memory management flaws in the Flash Player's runtime environment, potentially allowing attackers to escalate privileges, gain persistent access, or perform full system compromise. Organizations were advised to immediately update their Flash Player installations to versions that patched this vulnerability, as the attack surface was extensive given Flash Player's widespread deployment across enterprise networks and consumer environments.
The technical exploitation of this vulnerability required attackers to understand the specific memory layout patterns and type handling mechanisms within the Flash Player runtime. The type confusion issue manifested when the virtual machine encountered objects that were improperly initialized or when type information was corrupted during object manipulation. This flaw allowed attackers to manipulate the runtime's internal type tables and object references, creating conditions where controlled memory corruption could occur. The vulnerability was particularly challenging to detect and exploit because it relied on subtle timing and memory layout conditions that were difficult to predict. Security researchers noted that the exploitation required careful crafting of malicious SWF files that would trigger the specific conditions leading to type confusion. The attack was classified under the MITRE ATT&CK framework as part of the T1059.007 technique for Command and Scripting Interpreter: Visual Basic, though the actual exploitation involved Flash Player's ActionScript runtime rather than traditional scripting interpreters. This vulnerability demonstrated the inherent risks of complex virtual machine implementations and highlighted the importance of robust type validation mechanisms in interpreted languages. The patching process required careful coordination across different operating systems and platform variants, as each version of Flash Player required specific updates to address the type confusion issues. Organizations that had not yet migrated away from Flash Player faced significant risk exposure, particularly those with legacy systems or applications that still relied on Flash content for critical operations. The vulnerability underscored the importance of maintaining up-to-date software libraries and the dangers of running outdated multimedia plugins that could serve as attack vectors for sophisticated adversaries. Security teams were advised to implement network monitoring to detect attempts to access known vulnerable Flash Player versions and to ensure that all endpoints were properly updated to prevent exploitation.
The broader implications of this vulnerability extended beyond immediate exploitation capabilities to highlight systemic issues in multimedia runtime security. The type confusion flaw represented a fundamental breakdown in the Flash Player's memory safety mechanisms, where the virtual machine's type system failed to properly validate object integrity during runtime operations. This vulnerability demonstrated how complex interpreted environments could create attack surfaces that were difficult to predict or fully secure. The issue was particularly concerning because Flash Player was widely deployed across enterprise environments, making it an attractive target for nation-state actors and organized cybercriminal groups. The vulnerability's classification as a type confusion issue aligned with CWE-476 and related type safety violations that have historically been difficult to prevent through traditional security controls. Organizations that had not yet transitioned from Flash-based applications faced continued exposure to this and similar vulnerabilities, as the Flash Player ecosystem was inherently prone to such memory management issues. The remediation efforts required not just updating the Flash Player software but also implementing broader security monitoring to detect potential exploitation attempts. This vulnerability reinforced the need for organizations to maintain comprehensive software inventory management and to prioritize the timely patching of known vulnerabilities. The incident highlighted the importance of moving away from legacy multimedia technologies that had known security issues and demonstrated how even well-established software platforms could contain critical flaws that persisted across multiple versions. Security practitioners emphasized that this vulnerability served as a warning sign for the broader risks associated with interpreted runtime environments and the need for more secure alternative approaches to multimedia content delivery.