CVE-2019-7793 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 product versions across different release cycles. This vulnerability resides in the handling of malformed PDF files and occurs when the software attempts to read memory locations beyond the allocated buffer boundaries. The flaw manifests during the parsing of specific PDF objects where the application fails to properly validate array indices or buffer limits before accessing memory segments. This type of vulnerability falls under CWE-125 which specifically addresses out-of-bounds read conditions in software implementations. The vulnerability is particularly dangerous because it can be triggered through crafted malicious PDF documents that users might encounter while browsing or opening attachments.
The technical exploitation of this vulnerability occurs when an attacker crafts a PDF file containing malformed data structures that cause the Acrobat or Reader application to access memory locations that were not properly allocated for the current operation. When the application processes these malformed elements, it attempts to read beyond the intended buffer limits, potentially exposing sensitive data from adjacent memory regions. This memory access pattern can reveal information about the application's internal state, including stack contents, heap data, or other sensitive information that may be stored in adjacent memory locations. The out-of-bounds read operation itself may not directly lead to code execution but can provide attackers with sufficient information to facilitate more sophisticated attacks or to bypass security mechanisms.
From an operational perspective, this vulnerability creates significant risk for organizations that rely on Adobe Acrobat and Reader for document processing and viewing. Users who receive malicious PDF attachments or visit compromised websites could unknowingly trigger the vulnerability, leading to potential information disclosure without requiring any additional user interaction beyond opening the document. The impact extends beyond simple data leakage as the disclosed information could include cryptographic keys, session tokens, or other sensitive application data that could be leveraged for further attacks. This vulnerability particularly affects enterprise environments where PDF documents are frequently exchanged and where users may not be adequately trained to identify potentially malicious content.
Security mitigations for this vulnerability primarily focus on immediate remediation through official Adobe updates and patches. Organizations should prioritize updating all affected versions of Acrobat and Reader to the latest releases that contain the necessary fixes for this out-of-bounds read condition. Additionally, implementing PDF content filtering solutions and restricting PDF file handling through email gateways can provide additional layers of protection. Network administrators should consider deploying sandboxing solutions for PDF processing and implementing strict access controls for PDF documents from untrusted sources. The vulnerability also highlights the importance of regular security assessments and vulnerability management processes to identify and remediate similar issues before they can be exploited in the wild. This case demonstrates the critical nature of memory safety in document processing applications and the potential for seemingly benign vulnerabilities to create significant security risks when exploited in targeted attacks.