CVE-2011-0255 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-2011-0255 represents a critical memory corruption flaw within WebKit engine components that were integral to Apple Safari browsers prior to version 5.0.6. This vulnerability falls under the broader category of remote code execution flaws that have historically posed significant threats to web browser security. The issue stems from improper handling of memory allocation and deallocation processes within the WebKit rendering engine, which forms the core foundation of Safari's web page rendering capabilities. The vulnerability's classification aligns with CWE-125, which addresses out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are fundamental memory safety issues that can lead to arbitrary code execution.
The technical exploitation of this vulnerability occurs when a malicious web page is crafted to trigger specific memory corruption patterns within the WebKit engine. Attackers can construct web content that, when rendered by an affected Safari browser, causes the application to improperly manage memory resources, leading to unpredictable behavior including application crashes or complete system compromise. This type of vulnerability is particularly dangerous because it can be triggered entirely through web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website. The flaw demonstrates characteristics consistent with the ATT&CK framework's T1203 technique, which involves exploiting memory corruption vulnerabilities to gain unauthorized code execution.
The operational impact of CVE-2011-0255 extends beyond simple denial of service scenarios, as the memory corruption can potentially be leveraged to execute arbitrary code on affected systems. This capability transforms what might initially appear as a denial of service vulnerability into a serious security threat that could allow attackers to install malware, steal sensitive information, or establish persistent access to compromised systems. The vulnerability's exploitation pathway typically involves crafting malicious HTML content that triggers specific code paths within the WebKit engine, causing memory corruption that can be leveraged for privilege escalation. Organizations running affected Safari versions faced significant risk exposure since the vulnerability could be exploited through standard web browsing activities, making it particularly challenging to defend against.
Mitigation strategies for this vulnerability primarily centered on updating to Apple Safari version 5.0.6 or later, which contained patches addressing the underlying memory corruption issues. Security administrators were advised to implement immediate patch management procedures to ensure all affected systems received the necessary updates. The vulnerability highlighted the importance of regular security updates and the risks associated with running outdated browser versions. Additional defensive measures included implementing web content filtering solutions, deploying browser security extensions, and educating users about the dangers of visiting untrusted websites. From a compliance perspective, organizations needed to ensure their systems met minimum security standards, as this vulnerability could potentially violate regulatory requirements for maintaining secure computing environments. The incident underscored the critical nature of browser security and the need for continuous monitoring of security advisories from vendors like Apple to maintain robust defense-in-depth strategies.