CVE-2018-5056 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, specifically representing an insufficient bounds checking scenario where the application fails to properly validate array indices or buffer boundaries before accessing memory locations. The flaw exists in the handling of malformed PDF files where the software attempts to read data beyond the allocated memory buffer, potentially exposing sensitive information stored in adjacent memory locations.
The technical exploitation of this vulnerability occurs when a maliciously crafted PDF document is opened within the affected Adobe applications. The vulnerability manifests during the parsing process of PDF objects, particularly when processing arrays or streams where the application does not adequately verify the bounds of data access operations. Attackers can construct PDF files that trigger this out-of-bounds read condition by manipulating specific data structures within the PDF file format, causing the application to access memory regions that contain confidential data such as stack canaries, heap metadata, or other sensitive information from adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially provide attackers with insights into the memory layout of the running application. This information can be leveraged to aid in more sophisticated attacks such as heap spraying or return-oriented programming exploits. The vulnerability represents a significant risk in environments where Adobe Reader is used to process untrusted PDF content, as it can be exploited through social engineering attacks where users are tricked into opening malicious documents. The out-of-bounds read condition can lead to the exposure of memory contents that may include cryptographic keys, user credentials, or other sensitive data, making this vulnerability particularly dangerous in enterprise environments.
Organizations should prioritize immediate patching of all affected Adobe Acrobat and Reader installations to mitigate this vulnerability. The recommended mitigation strategy includes deploying the latest security updates from Adobe, which address the bounds checking issues in the PDF parsing engine. Additionally, implementing network-based protections such as PDF content filtering and sandboxing mechanisms can provide additional layers of defense. Security teams should also consider implementing monitoring solutions to detect suspicious PDF file access patterns and ensure that users are educated about the risks of opening untrusted PDF documents. This vulnerability demonstrates the critical importance of proper input validation and bounds checking in preventing memory corruption issues, aligning with ATT&CK technique T1059.007 for execution through PDF files and T1068 for privilege escalation through memory corruption exploits. The vulnerability highlights the need for robust software security practices and continuous vulnerability assessment to prevent similar issues in other software components that handle untrusted data inputs.