CVE-2016-7878 in Flash Player
Summary
by MITRE
Adobe Flash Player versions 23.0.0.207 and earlier, 11.2.202.644 and earlier have an exploitable use after free vulnerability in the PSDK s MediaPlayer class. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 10/08/2022
The vulnerability identified as CVE-2016-7878 represents a critical use after free flaw within Adobe Flash Player's PSDK MediaPlayer class implementation. This vulnerability affects multiple versions of the Flash Player runtime including versions 23.0.0.207 and earlier, as well as 11.2.202.644 and earlier, making it a widespread concern across both legacy and contemporary Flash Player installations. The flaw resides in how the MediaPlayer class manages memory allocation and deallocation processes, creating opportunities for malicious actors to exploit improper memory handling patterns.
The technical nature of this vulnerability falls under the CWE-416 category of Use After Free, which occurs when a program continues to reference memory after it has been freed by the system. In the context of Flash Player's PSDK MediaPlayer class, this vulnerability manifests when the application allocates memory for media playback objects and subsequently frees that memory while still maintaining references to it. Attackers can manipulate the playback sequence or media object lifecycle to trigger a scenario where freed memory is accessed, potentially allowing them to control the execution flow of the application. This type of vulnerability is particularly dangerous because it can be leveraged to execute arbitrary code within the context of the Flash Player process.
The operational impact of CVE-2016-7878 extends far beyond simple memory corruption, as successful exploitation can result in complete system compromise. When an attacker achieves arbitrary code execution through this vulnerability, they gain the ability to perform actions equivalent to the privileges of the Flash Player process, which typically runs with the same permissions as the user who launched the application. This opens pathways for privilege escalation, data exfiltration, system reconnaissance, and deployment of additional malware. The vulnerability is particularly concerning in enterprise environments where Flash Player remains in use despite its deprecated status, as it can serve as a gateway for lateral movement and persistent access within network infrastructures. The attack surface is broad since Flash Player was widely deployed across web browsers and applications, making exploitation relatively straightforward for threat actors.
Mitigation strategies for CVE-2016-7878 primarily focus on immediate remediation through software updates and long-term architectural changes. Adobe has released patches for affected versions, and organizations should prioritize immediate deployment of Flash Player updates to address this vulnerability. However, given that Adobe discontinued Flash Player support in 2020, organizations must consider complete removal of Flash Player from systems, as continued use presents ongoing security risks. Security controls should include web application firewalls that can detect and block Flash content, browser security policies that disable Flash execution, and network monitoring to identify potential exploitation attempts. Additionally, implementing the principle of least privilege and maintaining up-to-date threat intelligence feeds can help organizations detect and respond to exploitation attempts targeting this vulnerability. The ATT&CK framework categorizes such vulnerabilities under the T1059.007 technique for Command and Scripting Interpreter, as exploitation often involves executing malicious commands through the compromised Flash Player runtime environment.