CVE-2016-6971 in Acrobat Reader
Summary
by MITRE
Use-after-free vulnerability 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-2016-1089, CVE-2016-1091, CVE-2016-6944, CVE-2016-6945, CVE-2016-6946, CVE-2016-6949, CVE-2016-6952, CVE-2016-6953, CVE-2016-6961, CVE-2016-6962, CVE-2016-6963, CVE-2016-6964, CVE-2016-6965, CVE-2016-6967, CVE-2016-6968, CVE-2016-6969, CVE-2016-6979, CVE-2016-6988, and CVE-2016-6993.
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Analysis
by VulDB Data Team • 10/18/2024
This vulnerability represents a critical use-after-free flaw in Adobe Reader and Acrobat products that affects multiple versions across different operating systems. The issue stems from improper memory management where freed memory blocks are still accessed by the application, creating opportunities for attackers to manipulate program execution flow. The vulnerability impacts Adobe Reader versions before 11.0.18, Acrobat versions before 11.0.18, and various DC versions before their respective patch releases. Unlike other similar vulnerabilities in the same timeframe, this particular flaw operates through distinct attack vectors that make it particularly dangerous in targeted exploitation scenarios.
The technical implementation of this use-after-free vulnerability involves memory allocation and deallocation processes that fail to properly invalidate references to freed memory regions. When an application processes maliciously crafted PDF files, it may attempt to access memory that has already been freed, leading to unpredictable behavior that attackers can leverage to execute arbitrary code. This type of vulnerability falls under CWE-416 which specifically addresses use-after-free conditions in software applications. The flaw manifests when the application's parsing logic encounters malformed input data that triggers improper memory handling during PDF object processing.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables full system compromise through remote code execution. Attackers can craft malicious PDF documents that, when opened in vulnerable versions, trigger the memory corruption condition and subsequently execute malicious payloads. This represents a significant risk in enterprise environments where users frequently open PDF documents from untrusted sources. The vulnerability's presence in both Windows and OS X platforms increases its attack surface, making it particularly attractive to threat actors seeking cross-platform exploitation capabilities. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation.
Mitigation strategies for this vulnerability require immediate patching of affected Adobe products to the latest versions that contain memory management fixes. Organizations should implement strict PDF document filtering policies and consider deploying sandboxing solutions to isolate PDF processing activities. Security teams should monitor for indicators of compromise related to PDF-based attacks and ensure proper network segmentation to limit potential lateral movement. The vulnerability demonstrates the importance of regular security updates and proper memory management practices in preventing exploitation of similar flaws. Additionally, user education regarding the risks of opening untrusted PDF documents remains critical in reducing successful exploitation attempts.