CVE-2015-5566 in Flash Player
Summary
by MITRE
Use-after-free vulnerability in Adobe Flash Player before 18.0.0.232 on Windows and OS X and before 11.2.202.508 on Linux, Adobe AIR before 18.0.0.199, Adobe AIR SDK before 18.0.0.199, and Adobe AIR SDK & Compiler before 18.0.0.199 allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2015-5127, CVE-2015-5130, CVE-2015-5134, CVE-2015-5539, CVE-2015-5540, CVE-2015-5550, CVE-2015-5551, CVE-2015-5556, CVE-2015-5557, CVE-2015-5559, CVE-2015-5561, CVE-2015-5563, CVE-2015-5564, and CVE-2015-5565.
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Analysis
by VulDB Data Team • 06/13/2022
The CVE-2015-5566 vulnerability represents a critical use-after-free flaw in Adobe Flash Player and Adobe AIR runtime environments that was actively exploited in the wild during 2015. This vulnerability specifically affects Windows and macOS versions of Flash Player prior to 18.0.0.232, and Linux versions before 11.2.202.508, alongside various Adobe AIR implementations. The flaw stems from improper memory management where freed memory blocks are still referenced by subsequent operations, creating a predictable exploitation vector for malicious actors. This particular vulnerability operates independently from several other related issues including CVE-2015-5127 through CVE-2015-5565, making it a distinct threat that required separate patching efforts. The use-after-free condition occurs when the Flash Player runtime attempts to access memory that has already been deallocated, potentially allowing attackers to manipulate program execution flow through carefully crafted malicious content.
The technical exploitation of CVE-2015-5566 leverages the fundamental memory management flaw within Adobe's Flash Player runtime environment, where the application fails to properly validate memory references after objects have been freed. This vulnerability classifies under CWE-416, which specifically addresses use-after-free conditions in software development, making it particularly dangerous as attackers can potentially overwrite memory contents with malicious payloads. The exploitation typically occurs when a malicious web page or Flash content triggers a sequence where an object is freed from memory but references to that object persist, allowing attackers to control execution flow through controlled memory corruption. The vulnerability is particularly concerning because Flash Player was widely deployed across multiple operating systems and platforms, creating an extensive attack surface that adversaries could leverage through drive-by downloads or malicious web content.
From an operational impact perspective, CVE-2015-5566 enabled sophisticated attack campaigns that could lead to complete system compromise and persistent backdoor access. The vulnerability allowed attackers to execute arbitrary code with the privileges of the Flash Player process, which typically ran with user-level permissions but could potentially escalate to system-level access depending on the target environment. Security researchers documented numerous real-world exploitation attempts where this vulnerability was used in conjunction with other attack vectors to establish persistent presence on compromised systems. The widespread adoption of Flash Player made this vulnerability particularly dangerous as it could affect millions of users across different platforms, with the attack surface extending beyond individual user machines to enterprise networks where Flash content was commonly used in business applications. Organizations that had not updated their systems were vulnerable to remote code execution attacks that could bypass traditional security controls and potentially lead to data exfiltration or lateral movement within networks.
Organizations affected by CVE-2015-5566 were advised to implement immediate patching strategies as part of their incident response protocols, with the primary mitigation being the installation of Adobe's security patches for Flash Player and AIR runtime environments. The vulnerability was classified as a critical threat by major security vendors including Microsoft and various threat intelligence organizations, requiring urgent remediation efforts. Security teams were encouraged to implement network-based controls such as content filtering and web application firewalls to block potentially malicious Flash content while awaiting patch deployment. The remediation process required careful coordination across multiple platforms and versions, as different operating systems and runtime environments had distinct patching requirements. Additional mitigations included disabling Flash Player in web browsers, implementing sandboxing controls, and monitoring for unusual network activity that might indicate exploitation attempts. Organizations were also advised to conduct comprehensive vulnerability assessments to identify any systems that might have been compromised before patch deployment, as the vulnerability could be exploited to install persistent malware that would remain undetected without proper forensic analysis. The incident highlighted the importance of maintaining up-to-date security patches and implementing layered defense strategies to protect against zero-day exploits that could potentially bypass traditional security controls.