CVE-2019-8040 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions, 2019.012.20035 and earlier, 2019.012.20035 and earlier, 2017.011.30142 and earlier, 2017.011.30143 and earlier, 2017.011.30142 and earlier, 2015.006.30497 and earlier, and 2015.006.30498 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 • 07/28/2020
Adobe Acrobat and Reader applications contain a critical out-of-bounds read vulnerability that affects multiple version ranges including 2019.012.20035 and earlier, 2017.011.30142 and earlier, 2017.011.30143 and earlier, and 2015.006.30497 and earlier. This vulnerability resides in the PDF parsing functionality where the software fails to properly validate array indices when processing maliciously crafted PDF files. The flaw manifests when the application attempts to read memory locations beyond the allocated bounds of an array structure, potentially causing the software to access unauthorized memory regions. This type of vulnerability is classified as CWE-129 under the Common Weakness Enumeration framework, specifically addressing insufficient validation of array indices. The out-of-bounds read condition can be exploited by attackers who craft malicious PDF documents containing specially formatted data structures that trigger the vulnerable code path during document parsing. When successfully exploited, this vulnerability enables attackers to read sensitive memory contents that may include cryptographic keys, user credentials, or other confidential information. The operational impact extends beyond simple information disclosure as it can serve as a precursor to more severe attacks, potentially allowing adversaries to gather intelligence about the target system or application state. According to the MITRE ATT&CK framework, this vulnerability aligns with the technique T1059.007 for command and scripting interpreter and T1566.001 for spearphishing attachment, as attackers can leverage this flaw in targeted campaigns. The vulnerability's exploitation requires a user to open a malicious PDF file, making it a client-side attack vector that relies on social engineering tactics. The memory access pattern suggests that the application processes PDF objects without adequate bounds checking, particularly when handling embedded JavaScript or complex data structures within the document. Security researchers have identified that this flaw can be triggered through various PDF elements including but not limited to embedded fonts, annotations, or XObject streams. The information disclosure aspect of this vulnerability can be particularly dangerous in enterprise environments where sensitive documents containing confidential data may be processed by vulnerable applications. Organizations running affected versions of Adobe Acrobat and Reader should prioritize immediate patching to mitigate this risk. The vulnerability demonstrates a fundamental flaw in input validation that affects the core PDF processing engine of these applications, highlighting the importance of robust memory safety practices in document processing software. Given the widespread use of Adobe Reader across enterprise and consumer environments, this vulnerability represents a significant risk that could be exploited in targeted attacks against high-value targets. The out-of-bounds read condition essentially allows attackers to perform memory reconnaissance, potentially exposing application internals or system information that could aid in further exploitation attempts. This vulnerability underscores the critical need for regular security updates and proper code review processes that specifically address buffer over-read conditions in parsing libraries. The attack surface for this vulnerability is particularly broad due to the ubiquity of PDF document handling across different operating systems and platforms, making it a prime target for attackers seeking to exploit client-side vulnerabilities in document processing applications.