CVE-2017-16388 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 API 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
The vulnerability identified as CVE-2017-16388 represents a critical use after free flaw within Adobe Acrobat and Reader software across multiple version ranges including 2017.012.20098 and earlier, 2017.011.30066 and earlier, 2015.006.30355 and earlier, and 11.0.22 and earlier versions. This security issue resides within the JavaScript API engine component of Adobe's document processing software, which is widely utilized for executing JavaScript code within PDF documents. The flaw manifests when the application fails to properly manage memory references, creating opportunities for malicious actors to exploit the inconsistency between object lifecycles. The vulnerability specifically targets the improper handling of memory objects where a freed memory location is accessed after it has been deallocated, allowing attackers to manipulate memory contents through carefully crafted malicious PDF files.
The technical implementation of this use after free vulnerability stems from inadequate memory management practices within the JavaScript engine's object reference tracking mechanisms. When the PDF viewer processes JavaScript code containing malicious constructs, it may prematurely free memory associated with certain objects while still maintaining references to those locations. This creates a window where attackers can overwrite the freed memory with malicious code or data, effectively allowing them to corrupt the application's memory space. The mismatch between old and new object instances provides an attacker with unintended memory access capabilities that can be leveraged to execute arbitrary code within the context of the running application. This memory corruption can lead to complete system compromise, as the attacker gains the ability to manipulate the program's execution flow and potentially escalate privileges.
From an operational perspective, successful exploitation of CVE-2017-16388 can result in severe consequences for organizations relying on Adobe Acrobat and Reader for document processing. The vulnerability enables remote code execution without requiring user interaction beyond opening a malicious PDF file, making it particularly dangerous in phishing campaigns and targeted attacks. Attackers can leverage this flaw to install backdoors, exfiltrate sensitive data, or establish persistent access to compromised systems. The impact extends beyond individual user machines to enterprise environments where PDF documents are frequently shared and processed, potentially creating widespread security breaches. The vulnerability's exploitation potential aligns with attack techniques documented in the mitre attack framework under techniques such as execution through API calls and privilege escalation through memory corruption.
Organizations should implement immediate mitigations including prompt application of Adobe's security patches and updates, deployment of network-based protections such as web application firewalls, and implementation of email filtering solutions to prevent delivery of malicious PDF attachments. System administrators should consider disabling JavaScript execution in Acrobat Reader where possible, particularly in high-risk environments. The vulnerability classification aligns with CWE-416 which specifically addresses use after free conditions, and represents a significant risk factor in the context of the attack chain described in the attack framework where memory corruption vulnerabilities serve as primary attack vectors for privilege escalation and system compromise. Regular security assessments and vulnerability scanning should be conducted to ensure all affected systems are properly updated and protected against similar memory management flaws.