CVE-2016-4091 in Acrobat Reader
Summary
by MITRE
Heap-based buffer overflow in Adobe Reader and Acrobat before 11.0.16, Acrobat and Acrobat Reader DC Classic before 15.006.30172, and Acrobat and Acrobat Reader DC Continuous before 15.016.20039 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-4092.
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Analysis
by VulDB Data Team • 10/23/2024
The vulnerability identified as CVE-2016-4091 represents a critical heap-based buffer overflow affecting Adobe Reader and Acrobat products across multiple versions and operating systems. This flaw resides within the memory management mechanisms of these widely used PDF processing applications, creating a significant attack surface that has been exploited in the wild. The vulnerability specifically impacts versions prior to 11.0.16 for traditional Acrobat and Reader installations, as well as earlier releases of the DC Classic and DC Continuous editions, making it particularly concerning given the extensive deployment of these applications across enterprise environments. The flaw operates through unspecified vectors that differ from CVE-2016-4092, indicating a distinct code path that requires separate analysis and remediation efforts.
The technical implementation of this heap-based buffer overflow stems from inadequate bounds checking within the PDF parsing functionality of Adobe's applications. When processing specially crafted PDF documents, the application fails to properly validate the size of data structures allocated on the heap, allowing attackers to write beyond allocated memory boundaries. This memory corruption enables arbitrary code execution with the privileges of the user running the vulnerable application, effectively providing attackers with a powerful foothold for further system compromise. The vulnerability's classification as heap-based indicates that the overflow occurs in dynamically allocated memory segments, making exploitation more reliable and predictable compared to stack-based counterparts. The attack vector typically involves enticing users to open malicious PDF files through social engineering or phishing campaigns, leveraging the trusted nature of PDF document handling in business and personal environments.
The operational impact of CVE-2016-4091 extends far beyond simple code execution, as it represents a complete compromise of user systems and enterprise networks. Attackers can leverage this vulnerability to install backdoors, steal sensitive data, establish persistent access, and conduct lateral movement within compromised networks. The widespread adoption of Adobe Reader and Acrobat across organizations means that successful exploitation can affect thousands of endpoints simultaneously, creating cascading security incidents that can persist for extended periods. Organizations using these applications for document sharing, e-signature processing, and business-critical workflows face significant risk, as the vulnerability can be exploited through legitimate document delivery channels. The vulnerability's presence in both Windows and OS X operating systems creates a cross-platform threat that requires comprehensive remediation strategies across diverse computing environments. Security teams must also consider the potential for zero-day exploitation, as the vulnerability's discovery often occurs after initial deployment, leaving systems exposed during the critical window between vulnerability disclosure and patch installation.
Mitigation strategies for CVE-2016-4091 must address both immediate remediation needs and long-term security posture improvements. Organizations should prioritize immediate patch deployment for all affected versions of Adobe Reader and Acrobat, following Adobe's security bulletins and release notes for specific version requirements. Network-based protections including PDF content filtering, sandboxing mechanisms, and web application firewalls can provide additional defense layers while patches are deployed. The implementation of principle of least privilege and user education programs helps reduce the impact of successful exploitation attempts, as attackers often rely on user interaction to deliver malicious payloads. Security monitoring should include detection of unusual PDF processing activities, network connections initiated by Acrobat processes, and anomalous memory access patterns that may indicate exploitation attempts. The vulnerability aligns with several ATT&CK framework techniques including initial access through malicious files, execution through legitimate system processes, and privilege escalation. Organizations should also consider implementing application whitelisting policies that restrict execution of unauthorized PDF processing components, while maintaining detailed audit logs of PDF handling activities for incident response purposes. Compliance with industry standards such as those outlined in the CWE catalog for buffer overflow vulnerabilities reinforces the importance of proper input validation and memory management practices in preventing such critical security flaws from being exploited in operational environments.