CVE-2017-3113 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat Reader 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.30306 and earlier, and 11.0.20 and earlier has an exploitable use after free vulnerability in JavaScript engine when creating large strings. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 01/08/2021
Adobe Acrobat Reader contains a critical use after free vulnerability in its JavaScript engine that affects multiple versions including 2017.009.20058 and earlier, 2017.008.30051 and earlier, 2015.006.30306 and earlier, and 11.0.20 and earlier. This vulnerability arises during the processing of large string operations within the JavaScript engine, where memory management flaws allow for improper deallocation of memory resources followed by subsequent access to freed memory locations. The technical flaw represents a classic use after free condition that falls under CWE-416, which specifically addresses the use of memory after it has been freed. The vulnerability occurs when the JavaScript engine handles large string objects that require dynamic memory allocation, and during the string creation process, memory is freed prematurely while references to that memory remain accessible. This memory corruption issue enables attackers to manipulate the program execution flow by controlling the freed memory location, potentially allowing for arbitrary code execution. The operational impact of this vulnerability is severe as it provides attackers with a pathway to achieve remote code execution on vulnerable systems without requiring user interaction beyond opening a malicious PDF file. The attack vector leverages the JavaScript engine's handling of large strings, making it particularly dangerous in environments where users frequently open PDF documents from untrusted sources. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059.007 for JavaScript execution and T1068 for local privilege escalation. The exploitation process typically involves crafting a malicious PDF document containing specially crafted JavaScript code that triggers the memory management flaw during string operations, leading to memory corruption that can be leveraged for code execution. Organizations using affected versions of Adobe Acrobat Reader face significant risk as this vulnerability can be exploited in the wild, making it a high-priority target for threat actors seeking to compromise systems through document-based attacks. The vulnerability's exploitability is enhanced by the fact that it requires no user interaction beyond opening the malicious document, making it particularly dangerous in targeted attack scenarios. Security professionals should consider this vulnerability in their risk assessment frameworks as it represents a critical memory corruption issue that can lead to complete system compromise.
The use after free condition in Adobe Acrobat Reader's JavaScript engine demonstrates how improper memory management can create persistent security risks in widely deployed software applications. The vulnerability's presence across multiple versions indicates a fundamental flaw in the memory handling mechanisms of the JavaScript engine component, suggesting that the issue may stem from core architectural decisions rather than isolated coding errors. This type of vulnerability is particularly challenging to detect and remediate because it often requires deep analysis of memory allocation patterns and timing issues that occur during runtime execution. The specific context of large string creation makes this vulnerability particularly relevant in modern threat landscapes where attackers increasingly leverage complex document-based payloads to evade detection mechanisms. The impact extends beyond simple code execution to include potential privilege escalation and persistence mechanisms that attackers can utilize to maintain access to compromised systems. Organizations should implement immediate mitigations including disabling JavaScript execution in PDF readers, updating to patched versions, and implementing network-based controls to block potentially malicious PDF content. The vulnerability's classification under CWE-416 emphasizes the importance of proper memory management practices and highlights the need for comprehensive testing of memory handling code in security-critical applications. This particular flaw represents a significant concern for enterprise environments where Adobe Acrobat Reader is widely deployed and where document-based attacks remain a prevalent threat vector in cybersecurity incidents.