CVE-2018-4996 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 • 07/22/2024
Adobe Acrobat and Reader contain a critical use-after-free vulnerability that affects multiple versions across different release cycles. This vulnerability stems from improper memory management within the application's handling of PDF objects, creating a scenario where freed memory locations are accessed after being deallocated. The flaw manifests when the software processes malformed PDF files that trigger specific object cleanup sequences, leading to memory corruption that can be exploited by malicious actors.
The technical nature of this vulnerability places it firmly within the CWE-416 category, which specifically addresses use-after-free conditions in software systems. When a program frees a memory block but continues to reference that memory location, it creates a dangerous state where subsequent operations can corrupt data or execute arbitrary code. This particular vulnerability affects the JavaScript engine within Adobe Reader, where the improper handling of object references during PDF parsing operations allows attackers to manipulate memory layout and execute malicious payloads.
The operational impact of CVE-2018-4996 extends beyond simple code execution, as it represents a complete privilege escalation vector within the context of the current user. Attackers can craft malicious PDF documents that, when opened by vulnerable versions of Adobe Reader, trigger the use-after-free condition and subsequently gain arbitrary code execution capabilities. This vulnerability has been actively exploited in the wild, making it particularly dangerous for organizations that have not yet patched their systems. The attack surface is broad since Adobe Reader is widely deployed across enterprise environments, making it a prime target for social engineering campaigns that deliver malicious PDF attachments.
Security professionals should note that this vulnerability aligns with several tactics outlined in the MITRE ATT&CK framework, particularly those related to initial access through malicious documents and execution through legitimate system processes. The exploitation chain typically involves delivering a crafted PDF file that triggers the memory corruption, followed by code execution that can escalate privileges or establish persistence. Organizations should prioritize immediate patching of all affected versions, as the vulnerability has been confirmed to be actively exploited in targeted attacks. Additional mitigations include implementing strict PDF file validation policies, disabling JavaScript execution in Reader, and employing sandboxing techniques to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the risks associated with legacy software environments that may not receive timely security updates.