CVE-2019-7791 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 a use after free vulnerability. Successful exploitation could lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 06/16/2024
Adobe Acrobat and Reader contain a critical use after free vulnerability that affects multiple versions across different release cycles. This vulnerability stems from improper memory management within the software's handling of PDF objects, specifically when processing maliciously crafted PDF files. The flaw occurs when the application frees memory associated with a PDF object but continues to reference that memory location, creating a scenario where subsequent operations can corrupt or overwrite the freed memory region. This type of vulnerability falls under the CWE-416 category, which specifically addresses use after free conditions in software applications.
The technical exploitation of this vulnerability requires an attacker to craft a malicious PDF document that triggers the specific memory management error during document processing. When a victim opens such a document, the Acrobat or Reader application executes code that causes the targeted memory to be freed, yet the application continues to access that memory location through dangling pointers. This creates a predictable memory corruption scenario that can be leveraged to execute arbitrary code with the privileges of the affected user. The vulnerability is particularly dangerous because it can be triggered through simple document opening, making it suitable for phishing attacks and social engineering campaigns. According to ATT&CK framework, this vulnerability maps to technique T1203 (Exploitation for Client Execution) and potentially T1059 (Command and Scripting Interpreter) when executed code is used to establish further compromise.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise. Attackers can leverage the arbitrary code execution capability to install backdoors, steal sensitive data, or establish persistent access to compromised systems. The vulnerability affects a broad range of Adobe Reader versions, making it particularly concerning for enterprise environments where multiple versions may be in use. Organizations using these affected versions face significant risk, as the vulnerability can be exploited through various attack vectors including email attachments, web downloads, and malicious websites. The use after free condition creates a stable exploitation environment that allows attackers to reliably execute malicious payloads, making it a preferred target for sophisticated threat actors.
Mitigation strategies should focus on immediate version updates to patched releases, as Adobe has released security updates addressing this specific vulnerability. Organizations should implement strict document validation policies and consider sandboxing PDF viewing applications to limit potential damage from exploitation attempts. Network-based protections such as web application firewalls and email filtering systems can help detect and block malicious PDF files before they reach end users. Regular security awareness training should emphasize the dangers of opening unexpected PDF attachments and encourage users to verify document sources before opening. System administrators should monitor for exploitation attempts and implement endpoint detection and response solutions that can identify anomalous behavior associated with memory corruption attacks. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing proper software lifecycle management practices to prevent similar issues in the future.