CVE-2016-6938 in Acrobat Reader
Summary
by MITRE
Use-after-free vulnerability in Adobe Reader and Acrobat before 11.0.17, Acrobat and Acrobat Reader DC Classic before 15.006.30198, and Acrobat and Acrobat Reader DC Continuous before 15.017.20050 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-4255.
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Analysis
by VulDB Data Team • 10/03/2024
The CVE-2016-6938 vulnerability represents a critical use-after-free flaw affecting Adobe Reader and Acrobat products across multiple versions and operating systems. This vulnerability specifically impacts Adobe Reader versions prior to 11.0.17, Acrobat versions before 11.0.17, and both Classic and Continuous versions of Acrobat Reader DC before their respective patch levels of 15.006.30198 and 15.017.20050. The flaw exists on both Windows and macOS operating systems, making it a cross-platform threat that could potentially affect a wide range of users. The vulnerability allows remote attackers to execute arbitrary code on targeted systems, presenting a significant security risk that could be exploited without user interaction in many scenarios.
The technical nature of this use-after-free vulnerability stems from improper memory management within Adobe's PDF processing components. When handling maliciously crafted PDF files, the application fails to properly validate memory references, leading to situations where freed memory locations are still accessed or reused. This memory corruption pattern creates opportunities for attackers to manipulate program execution flow and inject malicious code into the target system. The vulnerability operates through unspecified vectors that differ from CVE-2016-4255, indicating it involves distinct code paths or processing methods within the Adobe Acrobat ecosystem. The flaw typically manifests when the application processes specific PDF elements that trigger memory deallocation followed by subsequent access to those freed memory regions.
The operational impact of CVE-2016-6938 extends beyond simple code execution, as it can enable full system compromise when exploited successfully. Attackers leveraging this vulnerability can potentially gain persistent access to affected systems, escalate privileges, and perform reconnaissance activities without detection. The cross-platform nature of the vulnerability means that security teams must implement comprehensive patching strategies across both Windows and macOS environments. Organizations using Adobe Reader and Acrobat products face significant risk exposure, particularly in environments where users frequently open PDF documents from untrusted sources. The vulnerability's potential for remote exploitation without user interaction makes it particularly dangerous in enterprise environments where PDF files are commonly shared and opened automatically.
Security mitigations for CVE-2016-6938 primarily focus on immediate patching and application hardening measures. Adobe released updates addressing this vulnerability in the specified versions, and organizations should prioritize deployment of these patches across all affected systems. Additional protective measures include implementing PDF sandboxing features, disabling automatic PDF opening in web browsers, and deploying network-based intrusion detection systems to monitor for exploitation attempts. Security professionals should also consider implementing application whitelisting policies that restrict execution of untrusted PDF files and employ email filtering solutions that scan for potentially malicious PDF attachments. Organizations should conduct vulnerability assessments to identify all systems running affected Adobe products and establish monitoring procedures to detect potential exploitation attempts. The vulnerability aligns with CWE-416, which describes the use-after-free error condition, and represents a significant concern under the ATT&CK framework's execution and privilege escalation tactics, particularly when considering the potential for persistent access and system compromise through successful exploitation.