CVE-2011-0163 in iOS
Summary
by MITRE
WebKit, as used in Apple Safari before 5.0.4 and iOS before 4.3, does not properly handle unspecified "cached resources," which allows remote attackers to cause a denial of service (resource unavailability) via a crafted web site that conducts a cache-poisoning attack.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2011-0163 represents a critical flaw in WebKit's handling of cached resources within Apple Safari and iOS browsers. This issue stems from the browser's inadequate management of unspecified cached resources, creating a pathway for malicious actors to manipulate the browser's caching mechanism. The vulnerability affects versions of Apple Safari prior to 5.0.4 and iOS prior to 4.3, indicating a widespread exposure across multiple Apple platforms that were prevalent during the early 2010s. The flaw manifests when the browser encounters crafted web content that exploits improper cache handling, leading to resource exhaustion or unavailability.
The technical implementation of this vulnerability involves WebKit's cache management system failing to properly validate or sanitize unspecified cached resources. When a malicious website delivers content that triggers this behavior, the browser's caching subsystem becomes compromised through what is known as cache poisoning. This attack vector specifically targets the browser's internal resource management, where cached data that should remain isolated or properly validated instead becomes corrupted or manipulated. The vulnerability operates at the application layer of the network stack, leveraging the browser's trust in cached resources without sufficient validation mechanisms. This weakness aligns with CWE-119, which addresses improper restriction of operations within a memory buffer, and represents a classic example of memory safety issues in web browser implementations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can effectively render web browsers unusable for legitimate users while the malicious cache poisoning persists. Attackers can craft websites that specifically target this flaw, causing legitimate browser sessions to become unresponsive or crash entirely. The resource unavailability affects not just individual web pages but potentially entire browsing sessions, as the poisoned cache can continue to serve corrupted content until manually cleared or the browser is restarted. This vulnerability particularly impacts users of older Apple operating systems and browsers, creating extended exposure windows where users may not have received security updates. The attack requires only a single visit to a malicious website to potentially compromise the browser's caching system, making it particularly dangerous for widespread exploitation.
Mitigation strategies for CVE-2011-0163 primarily involve updating to patched versions of Apple Safari and iOS, specifically Safari 5.0.4 and iOS 4.3 or later. System administrators should prioritize deployment of these security updates across all affected devices, particularly in enterprise environments where legacy systems may persist. Browser vendors and security teams should implement additional monitoring for cache-related anomalies and consider implementing more robust cache validation mechanisms. The vulnerability highlights the importance of proper input validation and resource management in browser implementations, aligning with ATT&CK technique T1211 which covers privilege escalation through cache poisoning attacks. Organizations should also consider implementing web filtering solutions and user education programs to reduce exposure to malicious websites that may exploit such vulnerabilities. Regular security assessments of browser configurations and caching behaviors can help identify potential weaknesses before they can be exploited by threat actors.