CVE-2017-6981 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3.2 is affected. macOS before 10.12.5 is affected. The issue involves the "iBooks" component. It allows attackers to execute arbitrary code in a privileged context via a crafted app that uses symlinks.
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Analysis
by VulDB Data Team • 09/02/2024
The vulnerability identified as CVE-2017-6981 represents a critical privilege escalation flaw within Apple's iBooks component affecting multiple operating systems. This security weakness exists in iOS versions prior to 10.3.2 and macOS versions prior to 10.12.5, demonstrating the widespread impact across Apple's ecosystem. The vulnerability stems from improper handling of symbolic links within the iBooks application, creating a pathway for malicious actors to gain elevated privileges through carefully crafted applications. The flaw specifically resides in how the system processes symlinked files during the iBooks rendering process, allowing attackers to manipulate file access patterns and execute code with system-level privileges.
The technical exploitation of this vulnerability follows a well-defined attack pattern that aligns with common privilege escalation techniques documented in the CWE database under CWE-264. Attackers can construct malicious applications that utilize symbolic links to bypass normal access controls and file system restrictions. When the iBooks component processes these crafted applications, it follows the symbolic links to unintended locations, potentially executing malicious code in a privileged context. This behavior creates a direct path for attackers to escalate their privileges from standard user level to system administrator level without proper authentication or authorization. The attack vector specifically targets the iBooks application's file processing logic, where symbolic link resolution occurs without adequate validation of the target paths.
The operational impact of CVE-2017-6981 extends beyond simple code execution, as it fundamentally compromises the security model of affected Apple systems. Once exploited, attackers can gain unrestricted access to system resources, potentially leading to complete system compromise. The vulnerability's persistence across multiple Apple platforms demonstrates the systemic nature of the flaw and its potential for widespread exploitation. Organizations and individual users running affected versions of iOS or macOS face significant risk, as the attack requires minimal sophistication and can be executed through standard application distribution channels. The privilege escalation capability means that even if users operate with standard accounts, they can be elevated to administrative privileges, undermining the principle of least privilege that forms the foundation of secure system design.
Security mitigations for this vulnerability primarily involve updating to the patched versions of iOS 10.3.2 and macOS 10.12.5, which address the symbolic link handling behavior in the iBooks component. System administrators should prioritize immediate deployment of these updates across all affected devices to eliminate the attack surface. Additional protective measures include implementing application whitelisting policies that restrict execution of untrusted applications, particularly those that might manipulate symbolic links. Network monitoring solutions should be configured to detect suspicious file access patterns that might indicate exploitation attempts. The vulnerability's classification under the ATT&CK framework would place it in the privilege escalation category, specifically targeting the "Exploitation for Privilege Escalation" technique. Organizations should also consider implementing sandboxing measures for iBooks and related applications to limit the potential damage from successful exploitation attempts. Regular security assessments and vulnerability scanning should include verification of patched system versions to ensure complete remediation of this and similar vulnerabilities.