CVE-2016-6994 in Acrobat Reader
Summary
by MITRE
Heap-based buffer overflow in Adobe Reader and Acrobat before 11.0.18, Acrobat and Acrobat Reader DC Classic before 15.006.30243, and Acrobat and Acrobat Reader DC Continuous before 15.020.20039 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-6939.
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Analysis
by VulDB Data Team • 10/18/2024
The heap-based buffer overflow vulnerability identified as CVE-2016-6994 represents a critical security flaw affecting Adobe Reader and Acrobat software across multiple versions and operating systems. This vulnerability specifically impacts Adobe Reader versions prior to 11.0.18, Acrobat versions before 11.0.18, and various Adobe Acrobat Reader DC Classic and Continuous versions before their respective patch releases. The flaw exists within the heap memory management mechanisms of these applications, creating a condition where maliciously crafted input can cause memory corruption that leads to arbitrary code execution. The vulnerability is distinct from CVE-2016-6939, indicating separate code paths and exploitation techniques that attackers can leverage to compromise systems.
The technical nature of this heap-based buffer overflow stems from improper input validation and memory handling within Adobe's document processing libraries. When the affected applications process maliciously formatted PDF files or other document types, the software fails to properly bounds-check memory allocations in heap regions. This allows attackers to overwrite adjacent memory locations with carefully crafted data, potentially leading to execution of malicious code with the privileges of the affected application. The vulnerability operates at the memory management level, where the application's heap allocator does not adequately verify that data written to allocated memory blocks remains within the designated boundaries, creating opportunities for memory corruption that can be exploited to gain unauthorized system access.
The operational impact of CVE-2016-6994 extends beyond simple code execution, as it provides attackers with a pathway to establish persistent access to compromised systems. Attackers can leverage this vulnerability through various delivery mechanisms including phishing emails containing malicious PDF attachments, compromised websites hosting malicious documents, or social engineering campaigns targeting specific organizations. The vulnerability affects both Windows and macOS operating systems, broadening the potential attack surface and making it particularly dangerous for enterprise environments where these platforms coexist. Successful exploitation can result in complete system compromise, data exfiltration, and the establishment of backdoors that persist across system reboots, making this vulnerability particularly attractive to advanced persistent threat actors.
Organizations should implement immediate mitigation strategies including mandatory patching of all affected Adobe Reader and Acrobat installations, deployment of network-based intrusion detection systems to monitor for exploitation attempts, and implementation of email filtering solutions to prevent delivery of malicious PDF attachments. The vulnerability aligns with several ATT&CK framework techniques including T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) where attackers can leverage the compromised applications to execute additional malicious code. Security teams should also consider implementing application whitelisting policies that restrict execution of unauthorized Adobe applications and establish network segmentation to limit lateral movement if exploitation occurs. The CWE classification for this vulnerability falls under CWE-121, Heap-based Buffer Overflow, which emphasizes the importance of proper memory management practices and bounds checking in software development to prevent such memory corruption vulnerabilities from being exploited in real-world scenarios.