CVE-2015-7656 in Flash Player
Summary
by MITRE
Use-after-free vulnerability in Adobe Flash Player before 18.0.0.261 and 19.x before 19.0.0.245 on Windows and OS X and before 11.2.202.548 on Linux, Adobe AIR before 19.0.0.241, Adobe AIR SDK before 19.0.0.241, and Adobe AIR SDK & Compiler before 19.0.0.241 allows attackers to execute arbitrary code via crafted actionImplementsOp arguments, a different vulnerability than CVE-2015-7651, CVE-2015-7652, CVE-2015-7653, CVE-2015-7654, CVE-2015-7655, CVE-2015-7657, CVE-2015-7658, CVE-2015-7660, CVE-2015-7661, CVE-2015-7663, CVE-2015-8042, CVE-2015-8043, CVE-2015-8044, and CVE-2015-8046.
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Analysis
by VulDB Data Team • 06/26/2022
The CVE-2015-7656 vulnerability represents a critical use-after-free flaw in Adobe Flash Player and AIR runtime environments that affects multiple platform versions across Windows, macOS, and Linux operating systems. This vulnerability specifically manifests when processing crafted actionImplementsOp arguments within the Flash Player runtime, creating a scenario where freed memory objects can be accessed and manipulated by malicious actors. The flaw falls under the broader category of memory corruption vulnerabilities that have historically been prime targets for exploit development due to their potential for arbitrary code execution. The vulnerability impacts Adobe Flash Player versions prior to 18.0.0.261 and 19.x versions before 19.0.0.245 on Windows and macOS platforms, while Linux versions are affected before 11.2.202.548. Additionally, Adobe AIR runtime environments before version 19.0.0.241 and corresponding SDK versions are equally vulnerable, making this a widespread issue affecting the entire Adobe runtime ecosystem.
The technical exploitation of this use-after-free vulnerability occurs when the Flash Player processes malformed actionImplementsOp bytecode instructions that trigger improper memory management behavior. When the runtime frees memory associated with an object but continues to reference that memory location, attackers can manipulate the freed memory to overwrite critical data structures or function pointers. This particular vulnerability operates through the ActionScript bytecode processing engine where the implementation of interfaces within the Flash runtime creates opportunities for memory corruption. The flaw demonstrates characteristics consistent with CWE-416 Use After Free, where memory is accessed after it has been freed, and aligns with ATT&CK technique T1059.007 for execution through Flash Player exploitation. The vulnerability requires specific conditions to be met including the presence of malicious SWF content that triggers the problematic bytecode path, making it a sophisticated target for social engineering attacks that deliver malicious Flash content.
The operational impact of CVE-2015-7656 extends beyond simple code execution to represent a complete compromise vector for enterprise environments where Flash Player remains active. 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 no user interaction beyond visiting a malicious website or opening a malicious file, making it particularly dangerous in targeted attack scenarios. The fact that this vulnerability affects multiple platforms including Windows, macOS, and Linux demonstrates the widespread nature of the threat, as organizations with mixed operating system environments face identical risks. Security researchers have noted that the use-after-free pattern in Flash Player exploits often leads to privilege escalation scenarios, where attackers can gain elevated system privileges through the exploitation process. The vulnerability's classification as a remote code execution flaw means that network-based attacks can be launched without requiring local system access, making it a preferred target for advanced persistent threat actors.
Mitigation strategies for CVE-2015-7656 should prioritize immediate patch deployment as the primary defense mechanism, with Adobe releasing updates to address the specific memory management issues within the actionImplementsOp processing code. Organizations should implement comprehensive patch management processes that include testing of Flash Player updates in controlled environments before widespread deployment. Network-based mitigations such as content filtering and web application firewalls can help reduce exposure by blocking known malicious Flash content, though these measures are not foolproof given the dynamic nature of attack delivery. Browser-level security controls including sandboxing and privilege separation can provide additional protection layers, though these are not complete solutions given that the vulnerability exists at the core runtime level. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates the critical need for organizations to maintain inventory control of Flash Player installations across their enterprise environments. Security teams should also implement monitoring for unusual Flash Player activity and network traffic patterns that might indicate exploitation attempts, as the use-after-free pattern often generates specific memory access patterns that can be detected through behavioral analysis. Given the nature of the vulnerability, the most effective long-term solution involves complete migration away from Flash Player technology to modern web standards, as Adobe officially discontinued Flash Player support in 2020, making such vulnerabilities increasingly difficult to address through patching alone.