CVE-2016-1121 in Acrobat Reader
Summary
by MITRE
Use-after-free vulnerability in Adobe Reader and Acrobat before 11.0.16, Acrobat and Acrobat Reader DC Classic before 15.006.30172, and Acrobat and Acrobat Reader DC Continuous before 15.016.20039 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-1045, CVE-2016-1046, CVE-2016-1047, CVE-2016-1048, CVE-2016-1049, CVE-2016-1050, CVE-2016-1051, CVE-2016-1052, CVE-2016-1053, CVE-2016-1054, CVE-2016-1055, CVE-2016-1056, CVE-2016-1057, CVE-2016-1058, CVE-2016-1059, CVE-2016-1060, CVE-2016-1061, CVE-2016-1065, CVE-2016-1066, CVE-2016-1067, CVE-2016-1068, CVE-2016-1069, CVE-2016-1070, CVE-2016-1075, CVE-2016-1094, CVE-2016-1122, CVE-2016-4102, and CVE-2016-4107.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2016-1121 represents a critical use-after-free flaw affecting Adobe Reader and Acrobat products across multiple versions and operating systems. This vulnerability specifically impacts Adobe Reader versions before 11.0.16, Acrobat versions before 11.0.16, and various Acrobat Reader DC Classic and Continuous versions before their respective patch releases. The flaw manifests in the handling of unspecified vectors within the software's memory management mechanisms, creating a condition where freed memory blocks can be accessed and potentially exploited by malicious actors. The vulnerability operates independently from numerous other related issues including CVE-2016-1045 through CVE-2016-1122 and several others, making it a distinct threat vector within Adobe's product ecosystem.
This use-after-free vulnerability stems from improper memory management practices where the application continues to reference memory locations that have already been freed during program execution. When an attacker can manipulate the application into freeing memory that is subsequently accessed, it creates opportunities for arbitrary code execution. The technical implementation involves the exploitation of memory corruption conditions that allow attackers to overwrite critical program data or execute malicious payloads directly within the target system's memory space. The vulnerability's classification aligns with CWE-416, which specifically addresses use-after-free conditions in software applications, making it particularly dangerous in enterprise environments where Adobe Reader remains widely deployed.
The operational impact of CVE-2016-1121 extends significantly across enterprise security landscapes, as Adobe Reader remains one of the most widely used PDF viewers in corporate and governmental environments. Attackers can leverage this vulnerability through malicious PDF files delivered via email phishing campaigns or compromised websites, requiring no additional privileges beyond normal user access. The exploitation process typically involves crafting specially formatted PDF documents that trigger the memory corruption when the vulnerable application processes the document content. This vulnerability is particularly concerning because it enables attackers to execute arbitrary code with the privileges of the user running Adobe Reader, potentially leading to complete system compromise. The vulnerability's presence in both classic and continuous delivery versions of Acrobat DC demonstrates the widespread nature of the flaw across Adobe's product lifecycle.
Mitigation strategies for CVE-2016-1121 primarily focus on immediate patch deployment and operational security measures. Organizations should prioritize updating all affected Adobe Reader and Acrobat installations to the latest versions that contain the relevant security fixes. The patch addresses the underlying memory management issues by implementing proper memory deallocation and reference validation mechanisms. Additional defensive measures include implementing strict email filtering policies to prevent malicious PDF attachments from reaching users, disabling automatic PDF processing in web browsers, and employing sandboxing technologies to contain potential exploitation attempts. Security teams should also monitor for indicators of compromise related to PDF-based attacks and implement network-based intrusion detection systems to identify potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving exploitation for code execution and privilege escalation, making it a significant concern for organizations implementing comprehensive threat hunting programs. The vulnerability's remediation requires coordinated patch management across enterprise environments while maintaining operational continuity through proper testing of updates in controlled environments before widespread deployment.