CVE-2011-0253 in Safari
Summary
by MITRE
WebKit, as used in Apple Safari before 5.0.6, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site, a different vulnerability than other WebKit CVEs listed in APPLE-SA-2011-07-20-1.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-0253 represents a critical memory corruption flaw within WebKit's JavaScript engine that affected Apple Safari versions prior to 5.0.6. This issue stems from improper handling of memory allocation and deallocation during JavaScript execution, creating opportunities for remote code execution through maliciously crafted web content. The vulnerability specifically impacts the JavaScriptCore engine component of WebKit, which is responsible for interpreting and executing JavaScript code in web browsers. Attackers could exploit this weakness by hosting specially crafted web pages that trigger memory corruption when the browser attempts to process JavaScript code, leading to unpredictable behavior and potential system compromise.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations. These memory corruption issues typically occur when the JavaScript engine fails to properly validate array indices or memory boundaries during code execution. The flaw manifests when WebKit processes certain JavaScript constructs that cause the engine to allocate memory in unexpected ways, potentially leading to buffer overflows or use-after-free conditions. The vulnerability's classification as a remote code execution flaw places it within the ATT&CK framework under T1059.007 for JavaScript and T1547.001 for privilege escalation through application flaws. The memory corruption occurs at the intersection of JavaScript interpretation and native code execution, where improper bounds checking allows attackers to manipulate memory layout and potentially execute arbitrary code with the privileges of the browser process.
The operational impact of this vulnerability extends beyond simple application crashes, as it enables full remote code execution capabilities that could be leveraged for advanced persistent threats. When exploited, the vulnerability allows attackers to bypass standard security measures such as address space layout randomization and data execution prevention, as the memory corruption occurs within the trusted browser environment. The affected Safari versions through 5.0.5 provided attackers with a reliable vector for privilege escalation and system compromise, particularly when users visited malicious websites or clicked on compromised links. This vulnerability was particularly dangerous in enterprise environments where users might encounter malicious content through phishing campaigns or compromised websites, as it could lead to complete system takeover without requiring user interaction beyond normal browsing behavior.
Mitigation strategies for CVE-2011-0253 focused primarily on immediate patching of affected Safari versions to 5.0.6 or later, which contained the necessary memory safety improvements and bounds checking enhancements. System administrators should have implemented browser security policies that restricted access to untrusted websites and enabled automatic updates for Safari components. Network-based mitigations included implementing web application firewalls and content filtering solutions that could detect and block known exploit patterns. The vulnerability highlighted the importance of regular security updates and the need for browser vendors to implement more robust memory safety mechanisms. Organizations should have conducted vulnerability assessments to identify systems running affected Safari versions and prioritized patch deployment according to risk levels. Additionally, user education programs emphasizing safe browsing practices and the dangers of visiting untrusted websites became essential components of the overall security posture. The remediation process required careful testing of patches to ensure compatibility with existing web applications while maintaining security integrity.