CVE-2016-7879 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 NetConnection class when handling an attached script object. 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-2016-7879 represents a critical use after free flaw within Adobe Flash Player's NetConnection class implementation. This vulnerability affects multiple versions of the Flash Player runtime, specifically those prior to 23.0.0.207 and 11.2.202.644, creating a significant attack surface for malicious actors targeting systems with outdated Flash Player installations. The flaw manifests when the Flash Player processes an attached script object within the NetConnection class, creating conditions where memory previously allocated to an object can be accessed after it has been freed, leading to potential exploitation opportunities.
The technical nature of this vulnerability stems from improper memory management within the Flash Player's handling of script objects in network connection contexts. When a NetConnection object interacts with attached script objects, the runtime fails to properly validate or manage the object lifecycle, allowing attackers to manipulate memory references after objects have been deallocated. This memory corruption vulnerability creates opportunities for attackers to execute arbitrary code on affected systems, as the use after free condition can be leveraged to overwrite memory locations with malicious payloads. The vulnerability's classification aligns with CWE-416, which describes use after free conditions that occur when software continues to reference memory after it has been freed, and represents a classic memory safety issue that has plagued software systems for decades.
The operational impact of this vulnerability extends beyond simple exploitation potential, as Flash Player remains widely deployed across enterprise environments and consumer systems. Attackers can leverage this vulnerability through malicious web content or specially crafted SWF files delivered via phishing campaigns, drive-by downloads, or compromised websites. The successful exploitation results in arbitrary code execution with the privileges of the Flash Player process, which typically runs with user-level permissions but can potentially be escalated to system-level access depending on the target environment. This vulnerability particularly affects organizations with legacy systems that have not updated their Flash Player installations, creating persistent security risks that can be exploited for data exfiltration, system compromise, or lateral movement within networks. The vulnerability's exploitation requires minimal user interaction, often only visiting a malicious website, making it particularly dangerous for widespread deployment.
Mitigation strategies for CVE-2016-7879 focus primarily on immediate remediation through Flash Player updates, as Adobe released patched versions to address the memory management issues within the NetConnection class. Organizations should implement comprehensive patch management processes to ensure all Flash Player installations are updated to versions that resolve this vulnerability, typically those beyond the affected versions mentioned in the CVE description. System administrators should also consider implementing network-level controls such as web application firewalls, content filtering solutions, and browser security policies that can block Flash content or restrict Flash Player functionality. Additionally, security teams should monitor for indicators of compromise related to this vulnerability, including unusual network connections, process execution patterns, or memory access anomalies that may suggest exploitation attempts. The remediation process should also include disabling Flash Player in browsers where possible, as the vulnerability's exploitation often occurs through web-based delivery mechanisms, and implementing security controls that align with the ATT&CK framework's mitigation strategies for malicious code execution through software exploitation techniques.