CVE-2011-3231 in Safari
Summary
by MITRE
The SSL implementation in Apple Safari before 5.1.1 on Mac OS X before 10.7 accesses uninitialized memory during the processing of X.509 certificates, which allows remote web servers to execute arbitrary code via a crafted certificate.
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Analysis
by VulDB Data Team • 11/24/2021
The vulnerability identified as CVE-2011-3231 represents a critical security flaw in Apple Safari's SSL implementation that affected versions prior to 5.1.1 on Mac OS X versions before 10.7. This issue stems from improper memory handling during X.509 certificate processing, creating a pathway for remote code execution through maliciously crafted certificates. The flaw specifically involves the browser's handling of uninitialized memory segments during SSL/TLS certificate validation, which can be exploited by attackers who control remote web servers.
The technical root cause of this vulnerability lies in the uninitialized memory access pattern within Safari's SSL certificate parsing code. When processing X.509 certificates, the application fails to properly initialize memory locations before reading certificate data, creating a potential for information disclosure and code execution. This memory handling error falls under the category of CWE-457, which describes the use of uninitialized variables, and more specifically aligns with CWE-125, which addresses out-of-bounds read conditions. The vulnerability creates a situation where attacker-controlled certificate data can influence memory contents in ways that allow arbitrary code execution.
From an operational perspective, this vulnerability presents a significant threat to users of affected Safari versions as it enables remote code execution through standard web browsing activities. An attacker who controls a web server can craft a malicious X.509 certificate that, when presented to an affected Safari browser, triggers the uninitialized memory access condition. This allows the attacker to execute arbitrary code with the privileges of the Safari process, potentially leading to complete system compromise. The attack requires no user interaction beyond visiting the malicious website, making it particularly dangerous in phishing scenarios or compromised web environments.
The attack vector for CVE-2011-3231 aligns with ATT&CK technique T1190, which describes exploitation of vulnerabilities in web browsers. This vulnerability specifically maps to the broader category of remote code execution through application flaws, where the attacker leverages the browser's SSL implementation to gain unauthorized system access. The impact extends beyond simple information disclosure to full system compromise, as the executed code operates within the browser's security context. Organizations should note that this vulnerability affects not only individual users but also enterprise environments where Safari is the default browser, potentially creating widespread compromise opportunities.
Mitigation strategies for this vulnerability include immediate installation of Apple's security patches, which address the uninitialized memory access issue in Safari's SSL implementation. System administrators should prioritize updating to Safari 5.1.1 or later versions on Mac OS X 10.7 and subsequent releases. Additionally, network administrators can implement certificate inspection controls and monitor for unusual certificate validation patterns. The vulnerability also underscores the importance of keeping all browser components updated, as SSL/TLS implementation flaws can provide attackers with direct execution paths. Organizations should consider implementing browser security policies that enforce automatic updates and maintain awareness of similar vulnerabilities in other browser implementations.