CVE-2016-0939 in Acrobat Reader
Summary
by MITRE
Adobe Reader and Acrobat before 11.0.14, Acrobat and Acrobat Reader DC Classic before 15.006.30119, and Acrobat and Acrobat Reader DC Continuous before 15.010.20056 on Windows and OS X allow attackers to execute arbitrary code or cause a denial of service (uninitialized pointer dereference and memory corruption) via unspecified vectors, a different vulnerability than CVE-2016-0931, CVE-2016-0933, CVE-2016-0936, CVE-2016-0938, CVE-2016-0942, CVE-2016-0944, CVE-2016-0945, and CVE-2016-0946.
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Analysis
by VulDB Data Team • 07/03/2022
Adobe Reader and Acrobat products have long been prime targets for cyber adversaries due to their widespread deployment and the complex nature of PDF processing. This vulnerability affects multiple versions of Adobe's flagship software across different platforms including Windows and macOS operating systems. The flaw manifests as an uninitialized pointer dereference combined with memory corruption issues that create opportunities for exploitation. These specific vulnerabilities represent distinct attack surfaces from other reported issues in the same timeframe, indicating that attackers can leverage these weaknesses to gain unauthorized access to systems or disrupt normal operations.
The technical implementation of this vulnerability stems from improper memory management within Adobe's PDF rendering engine. When processing malformed PDF documents, the application fails to properly initialize certain pointers before dereferencing them, leading to unpredictable behavior and potential code execution. This type of memory corruption vulnerability falls under the common weakness enumeration CWE-476 which specifically addresses NULL pointer dereferences. The uninitialized pointer dereference creates a scenario where attackers can manipulate memory locations to redirect execution flow or inject malicious code into the application's memory space.
From an operational perspective, the impact of this vulnerability extends beyond simple exploitation to include potential denial of service conditions that can disrupt business operations. Attackers can craft malicious PDF files that when opened by vulnerable Adobe applications trigger the memory corruption, potentially leading to system crashes or complete application instability. The attack surface is particularly concerning given Adobe Reader's prevalence in enterprise environments where users frequently open documents from untrusted sources. This vulnerability enables adversaries to leverage the application's legitimate PDF processing capabilities to execute arbitrary code with the privileges of the user running the vulnerable software.
The exploitation of this vulnerability aligns with tactics described in the attack framework under techniques related to privilege escalation and code execution. Attackers can leverage this issue to move laterally within networks or establish persistent access points through the compromised Adobe applications. Organizations that have not updated to the patched versions remain exposed to potential compromise, as the vulnerability allows for remote code execution without requiring user interaction beyond opening a malicious document. The memory corruption aspects of the flaw make detection difficult for traditional security controls, as the behavior can appear as random application crashes or unexpected system behavior rather than clear malicious activity patterns.
Mitigation strategies should prioritize immediate patch deployment across all affected systems, as Adobe has released security updates addressing this vulnerability. Organizations should implement additional controls such as PDF document sanitization, restricted browsing environments, and network segmentation to limit potential impact. Security teams should monitor for indicators of compromise related to PDF-based attacks and consider implementing application whitelisting policies to prevent execution of untrusted PDF files. The vulnerability highlights the importance of maintaining up-to-date software configurations and demonstrates how legacy applications can serve as persistent attack vectors when not properly maintained. Regular security assessments of document processing applications should be conducted to identify similar memory management issues that could lead to similar exploitation opportunities.