CVE-2017-16398 in Acrobat Reader
Summary
by MITRE
An issue was discovered in Adobe Acrobat and Reader: 2017.012.20098 and earlier versions, 2017.011.30066 and earlier versions, 2015.006.30355 and earlier versions, and 11.0.22 and earlier versions. This vulnerability is an instance of a use after free vulnerability in the JavaScript engine. The mismatch between an old and a new object can provide an attacker with unintended memory access -- potentially leading to code corruption, control-flow hijack, or an information leak attack. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 01/24/2021
This vulnerability exists in Adobe Acrobat and Reader software versions up to and including 2017.012.20098, 2017.011.30066, 2015.006.30355, and 11.0.22, representing a critical use after free condition within the JavaScript engine component. The flaw occurs when the software's JavaScript interpreter fails to properly manage object lifecycles, creating a scenario where memory previously allocated to an object can be accessed after the object has been freed, leading to unpredictable behavior and potential exploitation opportunities.
The technical implementation of this vulnerability stems from improper memory management within Adobe's JavaScript engine, specifically when handling objects that undergo rapid allocation and deallocation cycles. When an object is freed from memory but references to it persist, attackers can manipulate the memory layout to cause the freed object to be reallocated with malicious content. This creates a mismatch between the expected object state and actual memory contents, enabling attackers to control program flow through memory corruption. The vulnerability maps directly to CWE-416, which describes use after free conditions, and represents a classic example of how improper memory management can lead to arbitrary code execution.
The operational impact of this vulnerability is severe, as successful exploitation can result in complete system compromise through arbitrary code execution. Attackers can leverage this weakness to execute malicious payloads with the privileges of the affected application, potentially leading to privilege escalation, data theft, or persistent backdoor installation. The vulnerability affects multiple versions across different product lines, indicating a widespread issue that could impact enterprise environments where Adobe Reader is commonly deployed for document processing. Organizations with legacy systems running older versions of Adobe software face heightened risk due to the extended support windows that may not include patches for this specific vulnerability.
Mitigation strategies should prioritize immediate patching of affected software versions to address the underlying memory management flaw. Organizations should implement network segmentation to limit access to Adobe Reader functionality where possible, and deploy application whitelisting policies to restrict execution of potentially malicious JavaScript content. Additionally, security monitoring should focus on detecting anomalous memory access patterns and unexpected code execution within Acrobat processes. The ATT&CK framework categorizes this vulnerability under T1059.007 for JavaScript execution and T1068 for local privilege escalation, making it a critical target for defensive security controls. Regular security assessments of document processing workflows and user training on identifying suspicious PDF attachments remain essential defensive measures against exploitation attempts targeting this use after free vulnerability.