CVE-2018-12840 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2018.011.20058 and earlier, 2017.011.30099 and earlier, and 2015.006.30448 and earlier have an out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/17/2023
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability that affects multiple version ranges including 2018.011.20058 and earlier, 2017.011.30099 and earlier, and 2015.006.30448 and earlier. This vulnerability stems from improper bounds checking within the software's handling of specific file formats, particularly those involving embedded objects or complex data structures. The flaw allows an attacker to craft malicious PDF files that trigger memory access violations when the vulnerable software attempts to read data beyond allocated memory boundaries. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and represents a classic example of memory safety issues that have been extensively documented in cybersecurity literature. The out-of-bounds read occurs during the parsing of certain PDF elements where the application fails to validate array indices or buffer limits before accessing memory locations, potentially leading to the disclosure of sensitive information stored in adjacent memory regions. When exploited, this vulnerability can result in the exposure of confidential data, including but not limited to user credentials, system information, or other sensitive content that may be present in the memory space of the affected process. The operational impact extends beyond simple information disclosure, as the vulnerability could potentially be leveraged as a stepping stone for more sophisticated attacks, especially when combined with other exploitation techniques. Attackers typically craft malicious PDF files that contain specially formatted data structures designed to trigger the vulnerable code path, often involving malformed arrays or improperly structured embedded content. The vulnerability's exploitation requires the target user to open the malicious file, making social engineering a critical component of successful attacks. This aligns with ATT&CK technique T1204.002, which describes user execution through malicious files, and represents a common attack vector in targeted phishing campaigns. The security implications are particularly concerning given the widespread use of Adobe Acrobat and Reader across enterprise environments, where the disclosure of information could lead to significant data breaches or compromise of sensitive business information. Organizations utilizing these vulnerable versions face substantial risk of unauthorized information access, especially in environments where PDF files are frequently exchanged or processed. The vulnerability demonstrates the ongoing challenges in memory safety within complex document processing software and highlights the importance of regular security updates and patch management programs. The out-of-bounds read vulnerability specifically affects how the application manages memory allocation and access patterns, particularly when processing complex PDF structures that contain embedded objects, JavaScript, or other advanced features. This flaw represents a fundamental issue in the software's defensive programming practices, where proper input validation and memory boundary checking mechanisms are insufficiently implemented. The information disclosure aspect of this vulnerability can potentially expose system memory contents that may include cached data, user session information, or other sensitive elements that could aid in further exploitation attempts. Security researchers have identified this vulnerability as particularly dangerous due to its potential for being combined with other techniques such as heap spraying or information leak attacks to achieve more comprehensive system compromise. The remediation approach requires immediate patching of all affected versions, with organizations needing to implement comprehensive vulnerability management processes to prevent similar issues in the future. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing robust input validation controls in security-critical applications. Organizations should also consider implementing additional security controls such as PDF sandboxing, restricted file access, and network-based protection measures to mitigate the risk of exploitation. The vulnerability's classification under CWE-129 and its potential for information disclosure aligns with common patterns observed in document processing software vulnerabilities, where complex parsing logic creates numerous potential attack surfaces. This particular flaw underscores the need for comprehensive security testing of file parsing components, particularly in applications that handle untrusted input from external sources.