CVE-2018-4107 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.4 is affected. The issue involves the "PDFKit" component. It allows remote attackers to bypass intended restrictions on visiting URLs within a PDF document.
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Analysis
by VulDB Data Team • 07/27/2024
The vulnerability identified as CVE-2018-4107 represents a significant security flaw within Apple's macOS operating system affecting versions prior to 10.13.4. This issue specifically targets the PDFKit framework, which is responsible for handling PDF document rendering and interaction within the macOS environment. The flaw manifests as an improper access control mechanism that allows malicious actors to circumvent intended security restrictions designed to prevent unauthorized URL access within PDF documents. The PDFKit component is widely used throughout macOS applications for displaying and interacting with PDF content, making this vulnerability particularly concerning given its potential for widespread exploitation.
The technical nature of this vulnerability falls under the category of bypassing access controls, which aligns with CWE-284 access control vulnerabilities. Attackers can exploit this weakness to manipulate PDF documents in such a way that they can trigger unauthorized network requests or access external resources that should have been restricted by the PDF viewer's security policies. This occurs because the PDFKit framework fails to properly validate or enforce the intended restrictions on URL handling within PDF documents, allowing remote attackers to craft malicious PDF files that can bypass the normal security boundaries. The flaw essentially allows for arbitrary URL access that should have been blocked or restricted by default security policies.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential entry points for more sophisticated attacks. When users open malicious PDF documents, they may unknowingly trigger network connections to attacker-controlled servers, potentially leading to command and control communication, data exfiltration, or further exploitation through the established network connections. This vulnerability particularly affects enterprise environments where users frequently open PDF documents from untrusted sources, making it a prime target for phishing campaigns or targeted attacks. The remote nature of the attack means that exploitation can occur without requiring local system access or user interaction beyond opening the PDF document.
Organizations should implement immediate mitigations including updating to macOS 10.13.4 or later versions where this vulnerability has been patched. Security administrators should also consider implementing network-level restrictions to block access to known malicious domains and monitor for unusual network activity that might indicate exploitation attempts. The ATT&CK framework categorizes this type of vulnerability under privilege escalation and defense evasion techniques, as attackers can leverage such flaws to maintain persistence and avoid detection. Additional mitigations include configuring PDF viewers to disable automatic URL launching and implementing content filtering solutions that can detect and block potentially malicious PDF content before it reaches end users.