CVE-2018-12765 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 • 08/12/2024
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 document parsing functionality. This vulnerability resides in the way the software processes maliciously crafted pdf files, specifically when handling certain embedded objects or streams that exceed expected memory boundaries. The flaw manifests when the application attempts to read data from memory locations beyond the allocated buffer, potentially exposing sensitive information stored in adjacent memory regions. This type of vulnerability falls under CWE-125, which specifically addresses out-of-bounds read conditions that can result in information disclosure and potentially further exploitation. The issue represents a significant security risk as it allows attackers to craft malicious pdf documents that, when opened by vulnerable versions of Adobe Reader or Acrobat, can trigger the out-of-bounds read operation. The exploitation mechanism typically involves manipulating the structure of pdf objects such as streams, dictionaries, or arrays in a manner that causes the parser to access memory beyond its intended bounds. When successful, this vulnerability can lead to the disclosure of sensitive data including memory contents, encryption keys, or other confidential information that may be stored in adjacent memory locations. The operational impact extends beyond simple information disclosure, as this vulnerability can serve as a stepping stone for more sophisticated attacks, potentially enabling attackers to gather intelligence about the target system or application memory layout. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and control communications and T1068 for exploit for privilege escalation. The vulnerability affects a broad range of Adobe products and versions, making it particularly dangerous in enterprise environments where multiple legacy versions may be in use. The root cause lies in inadequate bounds checking within the pdf parsing engine, specifically in how the application handles certain object types during document rendering or processing operations. Security researchers have noted that this vulnerability is particularly concerning because it can be triggered through simple document opening actions, requiring no special user interaction beyond viewing the malicious document. The information disclosure aspect of this vulnerability can be leveraged by attackers to gather system information, application state data, or even partial memory contents that may reveal sensitive implementation details or cryptographic information. Organizations should prioritize immediate patching of affected versions to prevent exploitation, as the vulnerability does not require user interaction beyond opening a malicious document, making it particularly dangerous in targeted attack scenarios.
The vulnerability demonstrates a classic buffer over-read condition that can be exploited through carefully crafted pdf files containing malformed data structures. When the vulnerable application processes these malicious documents, it fails to properly validate the size or bounds of data structures before attempting to access them, leading to unintended memory access patterns. This particular weakness affects the pdf parsing component's handling of streams and object structures, where the parser assumes certain data lengths or structures without proper validation checks. The out-of-bounds read occurs during the processing of embedded content within pdf files, particularly when dealing with compressed or encoded data streams that are not properly validated against expected size constraints. This vulnerability represents a significant concern for organizations relying on Adobe Reader for document processing, as it can be exploited through simple phishing campaigns or malicious document delivery methods. The impact of information disclosure through this vulnerability can be substantial, potentially exposing encryption keys, system memory contents, or application-specific data that could aid in further exploitation attempts. From a defensive standpoint, this vulnerability highlights the importance of maintaining up-to-date software versions and implementing proper input validation measures. The vulnerability's presence in multiple product versions underscores the need for comprehensive patch management strategies across enterprise environments. Security professionals should note that this vulnerability operates at the application layer and can be particularly challenging to detect through traditional network-based security controls. The exploitation potential of this vulnerability makes it a prime target for advanced persistent threat actors seeking to gather intelligence or establish footholds within target environments. Organizations should consider implementing additional security controls such as pdf sandboxing, restricted file access, and monitoring for suspicious document access patterns to mitigate the risk posed by this vulnerability. The vulnerability's classification under CWE-125 emphasizes the need for robust bounds checking in all memory operations, particularly in applications that process untrusted data formats like pdf documents. This particular flaw demonstrates how seemingly minor input validation gaps can result in significant security implications, especially when dealing with complex document formats that require extensive parsing and processing operations.