CVE-2015-4438 in Acrobat Reader
Summary
by MITRE
Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC Classic before 2015.006.30060, and Acrobat and Acrobat Reader DC Continuous before 2015.008.20082 on Windows and OS X allow attackers to bypass JavaScript API execution restrictions via unspecified vectors, a different vulnerability than CVE-2015-4435, CVE-2015-4441, CVE-2015-4445, CVE-2015-4447, CVE-2015-4451, CVE-2015-4452, CVE-2015-5085, and CVE-2015-5086.
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Analysis
by VulDB Data Team • 06/01/2022
Adobe Reader and Acrobat versions prior to specific patched releases contain a critical vulnerability that undermines the JavaScript security model implemented within the software. This vulnerability affects multiple product lines including the classic Acrobat and Reader versions as well as the newer DC Classic and DC Continuous variants. The flaw enables attackers to circumvent the JavaScript API execution restrictions that are fundamental to preventing malicious code execution within the PDF processing environment. Unlike other vulnerabilities in the same advisory, this particular issue involves distinct attack vectors that specifically target the JavaScript sandbox mechanisms rather than other security controls. The vulnerability exists across both Windows and macOS operating systems, demonstrating its widespread impact potential. This weakness represents a significant bypass of the application's security model, allowing unauthorized access to restricted API functions that should normally be unavailable to untrusted JavaScript code.
The technical nature of this vulnerability stems from improper handling of JavaScript execution contexts within the Adobe Acrobat environment. When processing PDF documents containing malicious JavaScript, the software fails to properly enforce the security restrictions that typically isolate potentially dangerous API calls from the executing code. This allows attackers to access restricted functions that provide access to system resources, file operations, and other capabilities that should remain protected from user-controlled JavaScript. The vulnerability is particularly concerning because it operates at the core of the application's security architecture, specifically targeting the JavaScript engine's sandboxing mechanisms. The unspecified vectors suggest that the flaw may involve multiple attack paths including improper validation of API access requests or failure to properly isolate execution contexts during JavaScript processing. This type of vulnerability falls under the category of privilege escalation and sandbox bypass, which are categorized as CWE-284 for improper access control and CWE-264 for permissions, privileges, and access control.
The operational impact of this vulnerability is severe as it allows attackers to execute arbitrary code within the context of the Acrobat application, potentially leading to full system compromise. An attacker could craft malicious PDF documents that, when opened, would bypass JavaScript restrictions and execute malicious payloads with the privileges of the Acrobat process. This could result in data theft, system infiltration, or further exploitation of the compromised system. The vulnerability affects users across different operating systems, making it particularly dangerous in enterprise environments where multiple platforms are in use. Organizations relying on Acrobat for document processing face significant risk, as the vulnerability could be exploited through email attachments, web downloads, or other common attack vectors. The impact extends beyond simple code execution to include potential privilege escalation and system-level access that could allow attackers to maintain persistent access or escalate their privileges within the compromised environment.
Mitigation strategies for this vulnerability should focus on immediate patching of affected systems, as this represents a critical security flaw that requires prompt remediation. Organizations should prioritize updating to the patched versions of Adobe Reader and Acrobat, specifically targeting the versions mentioned in the advisory. Network segmentation and email filtering should be enhanced to prevent delivery of potentially malicious PDF files to end users. Security monitoring should be implemented to detect unusual JavaScript activity or attempts to access restricted API functions. Administrators should consider implementing additional controls such as disabling JavaScript execution entirely for untrusted documents or using sandboxing solutions to isolate Acrobat processes. The vulnerability highlights the importance of maintaining current security patches and implementing layered defense strategies. From an ATT&CK perspective, this vulnerability maps to techniques involving privilege escalation and sandbox evasion, making it particularly dangerous in targeted attack scenarios. Regular security assessments and vulnerability scanning should be conducted to identify systems that may not have been properly patched, as this type of vulnerability often remains undetected until exploitation occurs.