CVE-2018-5066 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader 2018.011.20040 and earlier, 2017.011.30080 and earlier, and 2015.006.30418 and earlier versions have an Out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure.
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Analysis
by VulDB Data Team • 08/11/2024
Adobe Acrobat and Reader versions prior to 2018.011.20040, 2017.011.30080, and 2015.006.30418 contain a critical out-of-bounds read vulnerability that stems from improper input validation within the PDF parsing functionality. This vulnerability falls under the CWE-129 weakness category, which specifically addresses insufficient bounds checking in input validation processes. The flaw occurs when the software attempts to read memory locations beyond the allocated buffer boundaries while processing maliciously crafted PDF files, particularly during the handling of embedded objects or malformed data structures within the document hierarchy. The vulnerability manifests when the application fails to properly validate array indices or object sizes before accessing memory regions, allowing attackers to manipulate the parsing logic through crafted PDF content.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to extract sensitive data from the application's memory space. When exploited successfully, the out-of-bounds read could potentially expose memory contents including but not limited to encryption keys, user credentials, system information, or other confidential data stored in the application's working memory. This type of vulnerability aligns with the ATT&CK technique T1005 - Data from Local System, where adversaries can leverage memory corruption vulnerabilities to access sensitive information. The attack surface is particularly concerning given that PDF readers are frequently used to open documents from untrusted sources, making this vulnerability highly exploitable in real-world scenarios.
The exploitation of CVE-2018-5066 requires an attacker to craft a malicious PDF document that triggers the vulnerable parsing code path when the target system opens the file. This typically involves manipulating specific fields within PDF objects such as arrays, dictionaries, or stream data structures to cause the application to read beyond its intended memory boundaries. The vulnerability represents a classic example of how buffer over-read conditions can be leveraged for information disclosure attacks, where the attacker can potentially extract arbitrary data from memory locations that should remain protected. Organizations using affected Adobe Reader versions face significant risk, as this vulnerability can be exploited through social engineering campaigns targeting end users to open malicious documents, or through automated scanning of web applications that serve PDF content. The remediation approach requires immediate patching of affected systems, as the vulnerability does not appear to have any effective workarounds that can be implemented without modifying the core application functionality.
Security professionals should note that this vulnerability demonstrates the importance of proper input validation and bounds checking in document processing applications, particularly those handling untrusted content. The flaw represents a common pattern in software vulnerabilities where insufficient validation of user-supplied data leads to memory corruption issues. Organizations should implement comprehensive patch management processes to address this vulnerability promptly, as the potential for exploitation increases with the prevalence of PDF-based attacks in modern threat landscapes. The vulnerability also highlights the need for regular security assessments of document processing libraries and the importance of maintaining up-to-date security patches for widely used software components.