CVE-2019-8191 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an out-of-bounds write vulnerability. Successful exploitation could lead to arbitrary code execution .
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Analysis
by VulDB Data Team • 01/16/2024
Adobe Acrobat and Reader applications contain a critical out-of-bounds write vulnerability that affects multiple version ranges including 2019.012.20040 and earlier, 2017.011.30148 and earlier, and 2015.006.30503 and earlier. This vulnerability falls under the CWE-787 category of out-of-bounds write conditions, where an attacker can manipulate memory access patterns to write data beyond the allocated buffer boundaries. The flaw occurs during the processing of maliciously crafted PDF files, specifically when the applications handle certain embedded objects or streams that trigger improper memory management during parsing operations. When exploited, this vulnerability allows an attacker to execute arbitrary code on the target system with the privileges of the user running the vulnerable software. The attack typically requires social engineering to convince users to open maliciously crafted PDF documents, making it particularly dangerous in targeted phishing campaigns or supply chain attacks. The vulnerability's exploitation path aligns with ATT&CK technique T1204.002 for 'User Execution' and T1059.001 for 'Command and Scripting Interpreter' as attackers can leverage this to establish persistent access through malicious code execution. The out-of-bounds write condition creates a memory corruption scenario that can be leveraged for privilege escalation attacks, potentially allowing attackers to gain system-level privileges. This vulnerability represents a significant risk to enterprise environments where users frequently open PDF documents from untrusted sources, making it a prime target for advanced persistent threat actors. Organizations should prioritize patching all affected versions of Adobe Acrobat and Reader to prevent exploitation attempts, as the vulnerability provides a direct path to remote code execution without requiring additional attack vectors.
The technical implementation of this vulnerability stems from insufficient bounds checking during PDF parsing operations, particularly when processing complex object structures or embedded content within PDF files. Attackers can craft PDF documents that contain malformed data structures designed to trigger the out-of-bounds write condition during normal document rendering or processing. The memory corruption occurs when the application attempts to write data to memory locations beyond the intended buffer boundaries, potentially overwriting critical program structures or executable code. This type of vulnerability is particularly challenging to detect and mitigate as it often requires specific memory layout conditions to be triggered successfully. The vulnerability's impact is amplified by the widespread use of Adobe Acrobat and Reader across enterprise environments, making it an attractive target for cybercriminals seeking to establish persistent access to sensitive networks. Security researchers have documented similar patterns in other Adobe products where out-of-bounds write conditions have been exploited to gain code execution privileges. The vulnerability's exploitation typically follows a predictable pattern of memory corruption followed by code execution, making defensive measures such as address space layout randomization and data execution prevention mechanisms critical for reducing the attack surface. Organizations should implement comprehensive patch management strategies to ensure all instances of affected software are updated promptly, as the vulnerability provides a direct pathway to system compromise without requiring complex attack chains or additional reconnaissance.
Mitigation strategies for this vulnerability should encompass both immediate patch deployment and broader security controls to reduce the attack surface. Organizations must prioritize updating all affected Adobe Acrobat and Reader installations to the latest versions that contain the necessary security patches. The patching process should include thorough testing to ensure compatibility with existing business applications and workflows while maintaining security posture. Network-based defenses such as PDF content filtering and sandboxing solutions can provide additional protection layers against exploitation attempts, particularly in environments where immediate patching is not feasible. Implementing principle of least privilege access controls and user education programs can help reduce the likelihood of successful exploitation through social engineering attacks. Security monitoring should include detection of suspicious PDF file handling activities and anomalous network connections that may indicate exploitation attempts. The vulnerability's classification as a critical out-of-bounds write condition makes it particularly susceptible to automated exploitation tools, requiring organizations to maintain active threat intelligence feeds and vulnerability management processes. Regular security assessments should verify that all endpoints are properly patched and that security controls are functioning as intended. The vulnerability's presence in multiple version ranges underscores the importance of maintaining comprehensive inventory management and vulnerability scanning processes to identify all potentially affected systems. Organizations should also consider implementing application whitelisting policies that restrict execution of unauthorized PDF processing applications, thereby reducing the attack surface for exploitation attempts.