CVE-2018-4971 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier have a Use-after-free vulnerability. Successful exploitation could lead to arbitrary code execution in the context of the current user.
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Analysis
by VulDB Data Team • 03/13/2023
Adobe Acrobat and Reader contain a critical use-after-free vulnerability in their handling of PDF documents that affects multiple product versions including 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier. This vulnerability falls under the CWE-416 category of Use-After-Free, where a program continues to reference memory after it has been freed, creating potential for exploitation through memory corruption attacks. The flaw occurs during the processing of maliciously crafted PDF files that trigger improper memory management during object destruction or cleanup operations. When a user opens a specially crafted PDF document, the application attempts to free memory associated with certain objects while simultaneously continuing to reference those same memory locations, leading to a state where subsequent memory operations can overwrite or corrupt the freed memory space.
The exploitation of this vulnerability can result in arbitrary code execution with the privileges of the current user, making it particularly dangerous in enterprise environments where users may open untrusted PDF documents. Attackers can craft malicious PDF files that, when opened by vulnerable versions of Acrobat or Reader, will trigger the use-after-free condition and subsequently execute malicious code. This type of vulnerability represents a significant threat vector in the ATT&CK framework under the T1059 category of Command and Scripting Interpreter, as successful exploitation can lead to full system compromise. The vulnerability is particularly concerning because it requires no special privileges beyond normal user access and can be delivered through email attachments, web downloads, or other common attack vectors.
The operational impact of CVE-2018-4971 extends beyond simple code execution, as it can enable attackers to establish persistent access, escalate privileges, or deploy additional malware payloads. Organizations running affected versions of Adobe Acrobat and Reader face significant risk of data breaches, system compromise, and potential lateral movement within their networks. The vulnerability demonstrates the importance of keeping software updated, as Adobe released patches for affected versions to address the memory management issues. Security professionals should prioritize patching this vulnerability immediately, as it has been actively exploited in the wild and represents a common target for advanced persistent threat actors. The use-after-free condition creates a predictable exploitation pattern that security researchers have documented extensively, making it easier for attackers to develop reliable exploit code for this specific vulnerability. Organizations should implement additional security measures such as PDF sandboxing, content filtering, and user education to reduce the attack surface while awaiting patch deployment.