CVE-2016-0991 in Flash Player
Summary
by MITRE • 01/25/2023
Use-after-free vulnerability in Adobe Flash Player before 18.0.0.333 and 19.x through 21.x before 21.0.0.182 on Windows and OS X and before 11.2.202.577 on Linux, Adobe AIR before 21.0.0.176, Adobe AIR SDK before 21.0.0.176, and Adobe AIR SDK & Compiler before 21.0.0.176 allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-0987, CVE-2016-0988, CVE-2016-0990, CVE-2016-0994, CVE-2016-0995, CVE-2016-0996, CVE-2016-0997, CVE-2016-0998, CVE-2016-0999, and CVE-2016-1000.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2016-0991 represents a critical use-after-free flaw in Adobe Flash Player and related Adobe AIR runtime environments that affected multiple platform versions across Windows, macOS, and Linux operating systems. This vulnerability falls under the CWE-416 category of Use After Free, where memory that has been freed is still accessed by the application, creating potential exploitation opportunities for malicious actors. The affected versions include Flash Player releases before 18.0.0.333 and 19.x through 21.x before 21.0.0.182 on Windows and OS X platforms, alongside Linux versions before 11.2.202.577, along with corresponding Adobe AIR and AIR SDK versions. The vulnerability's significance lies in its ability to allow remote code execution when exploited, making it a prime target for cybercriminals seeking to compromise systems through web-based attacks.
The technical implementation of this use-after-free vulnerability occurs when the Flash Player runtime processes malicious content that triggers a memory deallocation operation, followed by subsequent access to that freed memory location. This flaw typically manifests during the handling of specific multimedia or scripting elements within Flash applications, where improper memory management allows attackers to manipulate the execution flow. The vulnerability operates at the runtime level of the Flash Player environment, making it particularly dangerous as it can be triggered through web browsers that have Flash Player installed. According to the ATT&CK framework, this vulnerability maps to T1059.007 for Windows Command Shell and T1059.006 for PowerShell, as attackers can leverage the executed code to establish persistence mechanisms or escalate privileges within compromised systems.
The operational impact of CVE-2016-0991 extends beyond simple exploitation capabilities to encompass widespread system compromise across enterprise networks. Organizations running vulnerable Flash Player installations face significant risk exposure, particularly in environments where users regularly browse untrusted websites or receive email attachments containing malicious Flash content. The vulnerability's cross-platform nature means that organizations must implement comprehensive patch management strategies across all supported operating systems, including Windows, macOS, and Linux distributions. Attackers can leverage this vulnerability to execute arbitrary code with the privileges of the Flash Player process, potentially leading to full system compromise. The vulnerability's exploitation requires minimal user interaction, often occurring through drive-by downloads or malicious advertisements, making it particularly dangerous for organizations with less sophisticated security awareness programs.
Security professionals should prioritize immediate patch deployment for all affected versions of Adobe Flash Player and Adobe AIR environments, as the vulnerability has been actively exploited in the wild. The remediation process involves updating to the patched versions mentioned in the advisory, specifically targeting Flash Player versions 18.0.0.333, 21.0.0.182, and corresponding AIR versions 21.0.0.176. Organizations should also implement network-based protections including web application firewalls and content filtering solutions to block known malicious Flash content. Additionally, implementing browser security measures such as disabling Flash Player entirely or restricting its execution through browser security policies provides additional layers of defense. The vulnerability's classification as a remote code execution flaw aligns with ATT&CK techniques for privilege escalation and persistence, making comprehensive endpoint protection and monitoring essential for organizations to detect potential exploitation attempts. Given the widespread use of Flash Player in enterprise environments, security teams must conduct thorough vulnerability assessments to identify all systems running affected versions and implement appropriate mitigation strategies to prevent successful exploitation attempts.