CVE-2018-4277 in macOS
Summary
by MITRE
In iOS before 11.4.1, watchOS before 4.3.2, tvOS before 11.4.1, Safari before 11.1.1, macOS High Sierra before 10.13.6, a spoofing issue existed in the handling of URLs. This issue was addressed with improved input validation.
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Analysis
by VulDB Data Team • 04/05/2023
This vulnerability represents a URL spoofing flaw that affected multiple Apple operating systems including iOS, watchOS, tvOS, Safari, and macOS High Sierra. The issue stemmed from inadequate input validation mechanisms within the URL handling processes of these platforms. Attackers could exploit this weakness to craft malicious URLs that would appear legitimate to users while actually directing them to malicious destinations. The vulnerability specifically targeted the way these systems processed and displayed URL information, creating opportunities for social engineering attacks where users might be deceived into trusting fraudulent websites. This type of spoofing vulnerability falls under the CWE-601 vulnerability category, which encompasses open redirect vulnerabilities and URL manipulation issues. The flaw essentially allowed attackers to manipulate URL display strings in a way that could mislead users about the actual destination of web links.
The technical implementation of this vulnerability exploited the inconsistent handling of URL parsing and display across Apple's ecosystem. When users encountered web links or URL representations within these platforms, the systems failed to properly validate or sanitize the input before rendering it to the user interface. This inconsistency meant that attackers could craft URLs containing encoded characters, special sequences, or other manipulations that would be processed differently by the underlying URL parsing engines. The vulnerability was particularly concerning because it affected multiple platforms simultaneously, suggesting a systemic issue in how Apple handled URL validation at the core of their operating system components. The issue was addressed through enhanced input validation measures that improved the sanitization and verification of URL parameters before they were displayed or processed.
The operational impact of this vulnerability extended beyond simple phishing attacks to potentially enable more sophisticated exploitation scenarios. Users could be misled into believing they were visiting legitimate websites when they were actually navigating to attacker-controlled domains. This could lead to credential theft, malware delivery, or other malicious activities that rely on user trust in displayed URLs. Security researchers noted that the vulnerability was particularly dangerous in mobile environments where users might be more susceptible to social engineering attacks due to the smaller screen sizes and less sophisticated URL recognition capabilities. The cross-platform nature of the vulnerability meant that attackers could potentially exploit it across different Apple devices, increasing the attack surface and making it more difficult for users to protect themselves through device-specific mitigations. Organizations using Apple devices for business purposes needed to be particularly concerned about this vulnerability as it could compromise enterprise security if employees were tricked into visiting malicious sites.
Apple addressed this vulnerability through comprehensive input validation improvements across all affected platforms. The updates implemented stricter parsing rules for URL handling and enhanced the sanitization of URL parameters before display. These fixes were rolled out as part of the respective system updates including iOS 11.4.1, watchOS 4.3.2, tvOS 11.4.1, Safari 11.1.1, and macOS High Sierra 10.13.6. The mitigation strategy focused on ensuring that URL representations could not be manipulated to mislead users about the actual destination of web links. Organizations should have implemented prompt system updates across all affected Apple devices to protect their users from potential exploitation. The vulnerability serves as a reminder of the critical importance of proper input validation in preventing URL-based attacks, and the ATT&CK framework categorizes this type of vulnerability under the 'T1566' technique for 'Phishing' and 'T1071' for 'Application Layer Protocol' where URL manipulation is used for malicious purposes. Security teams should have monitored for any suspicious URL patterns or user behavior that might indicate exploitation attempts during the period when this vulnerability was active.