CVE-2016-6967 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-2016-6968, CVE-2016-6969, CVE-2016-6971, CVE-2016-6979, CVE-2016-6988, and CVE-2016-6993.
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Analysis
by VulDB Data Team • 10/18/2024
This use-after-free vulnerability exists in Adobe Reader and Acrobat products across multiple versions, specifically affecting Windows and macOS operating systems. The flaw represents a critical memory safety issue where freed memory blocks are still accessed by the application, creating opportunities for attackers to manipulate program execution flow. Unlike other vulnerabilities in the same advisory, CVE-2016-6967 operates through distinct attack vectors that exploit memory management weaknesses in the PDF processing engine. The vulnerability stems from improper handling of memory resources when processing maliciously crafted PDF files, where the application fails to properly validate object references after memory deallocation occurs. This particular weakness allows attackers to execute arbitrary code with the privileges of the current user, potentially leading to complete system compromise.
The technical implementation of this vulnerability involves a classic use-after-free condition where an attacker crafts a malicious PDF document containing specially constructed objects that trigger the memory management error. When the vulnerable application processes such a document, it deallocates certain memory structures while still maintaining references to them, creating a scenario where subsequent operations can overwrite or access the freed memory location. This memory corruption can be leveraged to inject and execute malicious code within the application's memory space, bypassing standard security controls. The vulnerability is particularly dangerous because it can be triggered through normal document opening operations, requiring no special privileges or user interaction beyond opening the malicious file. Attackers can exploit this condition to gain arbitrary code execution, potentially leading to privilege escalation, data exfiltration, or system persistence mechanisms.
The operational impact of CVE-2016-6967 extends beyond simple code execution, as it represents a significant threat vector for advanced persistent threats and zero-day exploitation campaigns. Organizations using affected versions of Adobe Reader and Acrobat face substantial risk exposure, particularly in environments where users frequently open PDF documents from untrusted sources. The vulnerability's exploitation can result in complete system compromise, data loss, and unauthorized access to sensitive information. Security analysts note that this vulnerability aligns with attack patterns described in the attack tree methodology, where attackers can progress from initial exploitation to full system control through well-crafted attack chains. The memory corruption nature of the vulnerability makes it particularly challenging to detect and prevent through traditional signature-based security measures, requiring more sophisticated behavioral analysis and memory protection mechanisms.
Mitigation strategies for CVE-2016-6967 focus primarily on immediate patching and system hardening approaches. Adobe released security updates for all affected versions, including Acrobat and Acrobat Reader DC Classic and Continuous, making it essential for organizations to apply these patches promptly. System administrators should implement strict document handling policies, including sandboxing PDF processing and restricting access to untrusted PDF sources. Network-based defenses can include PDF file inspection and filtering mechanisms that identify potentially malicious content before it reaches end-user systems. The vulnerability demonstrates characteristics consistent with CWE-416, which describes use-after-free conditions in software, and aligns with ATT&CK techniques involving privilege escalation and code execution through memory corruption vulnerabilities. Organizations should also consider implementing application whitelisting policies and regular security assessments to identify and remediate similar vulnerabilities across their software ecosystems.