CVE-2018-4409 in Safari
Summary
by MITRE
A resource exhaustion issue was addressed with improved input validation. This issue affected versions prior to iOS 12.1, tvOS 12.1, Safari 12.0.1, iTunes 12.9.1, iCloud for Windows 7.8.
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Analysis
by VulDB Data Team • 04/08/2020
The vulnerability identified as CVE-2018-4409 represents a critical resource exhaustion flaw that impacted multiple Apple platforms and applications. This issue stems from insufficient input validation mechanisms within the affected software components, creating opportunities for malicious actors to consume system resources excessively. The vulnerability affects iOS versions prior to 12.1, tvOS versions prior to 12.1, Safari browser versions prior to 12.0.1, iTunes versions prior to 12.9.1, and iCloud for Windows versions prior to 7.8, indicating a widespread impact across Apple's ecosystem. The flaw specifically manifests when the affected applications process malformed or untrusted input data without proper validation checks, leading to potential system instability and service disruption.
The technical implementation of this vulnerability involves the exploitation of insufficient bounds checking and input sanitization routines within Apple's software stack. When legitimate input data is processed without adequate validation, the system may allocate excessive memory resources or consume processing cycles in an attempt to handle malformed data. This behavior creates a condition where an attacker can craft specific input sequences that cause the application to consume increasing amounts of system resources over time. The vulnerability aligns with CWE-400, which categorizes resource exhaustion issues as a fundamental weakness in software design. Attackers can leverage this flaw through various vectors including web content delivery, file processing, or network communication protocols that the affected applications utilize for data handling.
The operational impact of CVE-2018-4409 extends beyond simple denial-of-service conditions to potentially enable more sophisticated attack scenarios. Systems affected by this vulnerability may experience complete resource exhaustion, leading to application crashes, system instability, or complete device unresponsiveness. In mobile environments, this could result in complete device lockup, requiring manual reboot procedures and potentially disrupting critical user workflows. The vulnerability's impact is particularly concerning given the widespread adoption of affected versions across Apple's user base, suggesting that a significant number of devices could be vulnerable to exploitation. Network-based attacks could potentially leverage this flaw to target multiple devices simultaneously, amplifying the operational disruption potential. The affected applications including Safari browser and iTunes present additional attack surface considerations, as these components frequently process untrusted data from web sources and external devices.
Mitigation strategies for CVE-2018-4409 primarily focus on immediate software updates and patches provided by Apple. Users should immediately upgrade to the affected software versions that include the necessary input validation improvements. System administrators should implement proactive monitoring for any unusual resource consumption patterns that might indicate exploitation attempts. The vulnerability's remediation demonstrates Apple's approach to addressing security flaws through comprehensive input validation improvements, which aligns with defensive programming best practices and industry standards for secure software development. Organizations should also consider implementing network segmentation and access controls to limit potential exploitation vectors, particularly for systems that cannot be immediately updated. The vulnerability serves as a reminder of the importance of robust input validation in preventing resource exhaustion attacks, and its remediation provides a model for how software vendors should address similar weaknesses in their codebases.