CVE-2016-0941 in Acrobat Reader
Summary
by MITRE
Use-after-free vulnerability in the Search object implementation in 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 allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-0932, CVE-2016-0934, CVE-2016-0937, and CVE-2016-0940.
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Analysis
by VulDB Data Team • 07/03/2022
The CVE-2016-0941 vulnerability represents a critical use-after-free flaw within Adobe Reader and Acrobat's Search object implementation across multiple product versions. This vulnerability specifically affects Windows and macOS operating systems and enables remote code execution through unspecified attack vectors that distinguish it from related vulnerabilities such as CVE-2016-0932, CVE-2016-0934, CVE-2016-0937, and CVE-2016-0940. The flaw manifests in the improper handling of memory objects where freed memory locations are accessed after being deallocated, creating a predictable exploitation surface for malicious actors. The vulnerability is classified under CWE-416, which specifically addresses use-after-free conditions in software implementations, making it a direct descendant of memory safety issues that have plagued software applications for decades. This type of vulnerability is particularly dangerous because it allows attackers to manipulate the program's memory layout and potentially overwrite critical function pointers or execute arbitrary code within the context of the vulnerable application. The attack surface is broad as it affects both the traditional Acrobat and Reader DC Classic versions as well as the newer DC Continuous releases, indicating a widespread implementation flaw that spans multiple product lines and update cycles.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious PDF document containing specially formatted search objects that trigger the flawed memory management routine. When the vulnerable application processes these objects, it frees memory associated with the Search object but continues to reference that memory location, creating a scenario where subsequent memory allocations might reuse the freed space. This allows attackers to inject malicious code into the freed memory region and redirect program execution flow to their payload. The exploitation process typically involves precise memory manipulation and often requires multiple stages to achieve reliable code execution. Attackers can leverage this vulnerability to bypass modern security protections such as DEP, ASLR, and stack canaries by carefully controlling the memory layout and using techniques like return-oriented programming or just-in-time compilation to achieve their objectives. The vulnerability's impact is amplified by the widespread use of Adobe Reader and Acrobat across enterprise environments, making it an attractive target for nation-state actors and cybercriminal organizations seeking to compromise large numbers of systems. The specific vectors that trigger this vulnerability remain undisclosed, but they likely involve complex interactions between PDF parsing components and the underlying search functionality that handles user input and document content.
The operational impact of CVE-2016-0941 extends far beyond simple privilege escalation or local code execution, as it represents a significant threat to enterprise security infrastructure and user data integrity. Organizations that rely heavily on PDF processing for document sharing, legal proceedings, and business communications face substantial risk from this vulnerability, as a single malicious PDF document could compromise entire networks through targeted attacks on executives, legal teams, or administrative personnel. The vulnerability's presence in both classic and continuous delivery versions of Acrobat DC indicates that the flaw has persisted across multiple release cycles, suggesting either inadequate code review processes or persistent memory management issues within Adobe's core libraries. Security teams must consider this vulnerability as part of their broader threat landscape, particularly when evaluating the risk of zero-day exploits in widely deployed software applications. The vulnerability's classification under the broader category of memory safety issues aligns with ATT&CK technique T1059, which encompasses various code execution methods that leverage application vulnerabilities, and T1203, which addresses exploitation of software vulnerabilities for privilege escalation. This makes it particularly relevant for organizations implementing security controls based on MITRE ATT&CK framework, as the vulnerability represents a clear path for attackers to achieve their objectives through well-established exploitation methodologies.
Organizations affected by CVE-2016-0941 should implement immediate mitigations including mandatory software updates to the patched versions of Adobe Reader and Acrobat, specifically versions 11.0.14, 15.006.30119, and 15.010.20056 respectively. Network-based mitigations should include PDF content filtering and sandboxing solutions that prevent automatic execution of potentially malicious PDF content. System administrators should also consider implementing application whitelisting policies that restrict the execution of Adobe Reader and Acrobat to trusted environments, particularly in high-risk sectors such as finance, government, and healthcare. The vulnerability's exploitation requires minimal user interaction, making it particularly dangerous in environments where users frequently open PDF documents from untrusted sources. Security monitoring should focus on detecting unusual PDF processing activities and potential exploitation attempts through network traffic analysis and endpoint detection systems. Adobe's official patch releases address the underlying use-after-free condition by implementing proper memory management practices and adding additional validation checks to prevent the premature freeing of objects that remain referenced elsewhere in the application. These patches typically include stack canary implementations, improved memory deallocation routines, and enhanced input validation for search-related PDF objects. The vulnerability serves as a reminder of the importance of regular security updates and the need for organizations to maintain comprehensive patch management programs that can quickly respond to critical vulnerabilities in widely used software applications.