CVE-2019-7803 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2019.010.20100 and earlier, 2019.010.20099 and earlier, 2017.011.30140 and earlier, 2017.011.30138 and earlier, 2015.006.30495 and earlier, and 2015.006.30493 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 • 09/17/2023
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability that affects multiple version ranges including 2019.010.20100 and earlier, 2019.010.20099 and earlier, 2017.011.30140 and earlier, 2017.011.30138 and earlier, 2015.006.30495 and earlier, and 2015.006.30493 and earlier. This vulnerability stems from improper input validation within the software's document parsing mechanisms, specifically when processing maliciously crafted pdf files. The flaw manifests as an out-of-bounds read condition where the application attempts to access memory locations beyond the allocated buffer boundaries during pdf file processing. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of input buffers, and represents a fundamental weakness in input validation that can lead to memory corruption issues. The vulnerability is particularly dangerous because it can be exploited through social engineering attacks where users unknowingly open malicious pdf attachments, making it a prime target for targeted attacks. When exploited successfully, this vulnerability can lead to information disclosure as the out-of-bounds read may expose sensitive memory contents including encryption keys, user credentials, or other confidential data stored in adjacent memory locations. The impact extends beyond simple information disclosure as it can potentially enable further exploitation techniques such as remote code execution, though the immediate risk is primarily data exposure. The vulnerability is classified under the ATT&CK framework as part of the T1203 - Exploitation for Client Execution technique, where adversaries leverage application vulnerabilities to execute malicious code on target systems. Organizations using affected Adobe products face significant risk as these applications are widely deployed across enterprise environments and are frequently used to process sensitive documents. The exploitation requires minimal user interaction beyond opening a malicious document, making it particularly effective for phishing campaigns and targeted attacks. Security professionals should note that this vulnerability represents a common pattern of memory safety issues that affect legacy software applications, particularly those handling complex binary formats like pdf documents. The root cause lies in inadequate bounds checking during document parsing operations where the application fails to properly validate the size and structure of pdf elements before attempting to access them. This vulnerability demonstrates the ongoing challenges in maintaining memory safety in complex document processing applications and highlights the importance of regular security updates and patch management programs. The affected versions span multiple major releases, indicating this is a persistent issue that has not been fully addressed in the software lifecycle, requiring immediate attention from security teams to implement mitigations and updates.
The technical exploitation of this vulnerability occurs when a malicious pdf file contains specially crafted data structures that cause the Acrobat or Reader application to read beyond allocated memory boundaries. During normal pdf processing, the application expects certain data formats and structures, but when these expectations are violated through crafted input, the memory access patterns become unpredictable. This type of vulnerability is particularly challenging to detect through automated scanning as it often requires specific conditions to be met during document parsing. The out-of-bounds read can potentially expose sensitive information from adjacent memory regions, including cached data, application state information, or even partial content from other processes running on the same system. The vulnerability's impact is amplified by the widespread use of Adobe Acrobat and Reader across various industries including finance, healthcare, and government sectors where sensitive data processing occurs. From a security perspective, this vulnerability represents a classic example of how legacy software can contain fundamental flaws that persist across multiple versions, creating long-term exposure windows for attackers. The lack of proper bounds checking in the document parsing pipeline creates opportunities for attackers to extract information from memory locations that should remain protected. Organizations should implement immediate mitigations including disabling pdf processing in web browsers, implementing strict content filtering, and ensuring all systems are updated with the latest security patches. The vulnerability also underscores the importance of application sandboxing and privilege separation techniques that can limit the potential damage from such exploits. Security teams should monitor for indicators of compromise related to pdf-based attacks and implement network-based detection measures to identify potential exploitation attempts. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and the risks associated with running legacy applications that may contain unpatched security flaws. The presence of this vulnerability across multiple product versions indicates that Adobe's security team needs to address fundamental issues in their document processing architecture rather than simply patching individual instances of the problem.