CVE-2019-8218 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure .
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Analysis
by VulDB Data Team • 01/16/2024
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability identified as CVE-2019-8218 affecting multiple version ranges including 2019.012.20040 and earlier, 2017.011.30148 and earlier, and 2015.006.30503 and earlier. This vulnerability resides in the handling of PDF file structures where the software fails to properly validate array indices before accessing memory locations, creating a scenario where maliciously crafted PDF documents can trigger unauthorized memory access patterns. The flaw manifests when the application processes malformed PDF objects that contain oversized or negative array indices, leading to the reading of data from memory locations outside the intended buffer boundaries. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of input buffers, and represents a classic example of memory safety issues that have been extensively documented in the cybersecurity community. The out-of-bounds read condition occurs during the parsing of PDF content streams where the software attempts to access array elements without proper bounds checking, potentially exposing sensitive information stored in adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for more sophisticated attacks within the context of the ATT&CK framework's initial access and persistence phases. An attacker could leverage this vulnerability to extract memory contents including encryption keys, user credentials, or other sensitive data that might be stored in memory regions adjacent to the vulnerable code paths. The exploitation requires a user to open a specially crafted malicious PDF file, which aligns with the social engineering tactics commonly used in targeted attacks. The vulnerability's presence in multiple version ranges suggests it was likely introduced in a common codebase and maintained across different release cycles, indicating a systemic issue in the PDF parsing libraries used by Adobe's products. Security researchers have noted that this class of vulnerability often serves as a stepping stone for more complex attacks, as the information disclosure can reveal patterns that aid in bypassing security mechanisms or identifying additional attack vectors.
Organizations should implement immediate mitigations including prompt application of Adobe's security patches, which address the root cause by introducing proper bounds checking mechanisms in the PDF parsing routines. Network-based defenses such as PDF content filtering and sandboxing solutions can provide additional protection layers while patches are being deployed. The vulnerability demonstrates the importance of input validation and memory safety practices, particularly in software handling untrusted data formats like PDF documents. Security teams should monitor for indicators of compromise related to PDF-based attacks and consider implementing automated patch management systems to ensure timely remediation across all affected systems. The incident highlights the ongoing challenges in maintaining memory safety in large software applications and underscores the need for continuous security assessments of core libraries and parsing components. Organizations should also consider implementing user education programs to reduce the risk of successful exploitation through social engineering attacks that rely on users opening malicious PDF attachments.