CVE-2008-4231 in iPhone OS
Summary
by MITRE
Safari in Apple iPhone OS 1.0 through 2.1 and iPhone OS for iPod touch 1.1 through 2.1 does not properly handle HTML TABLE elements, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted HTML document.
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Analysis
by VulDB Data Team • 04/13/2025
The vulnerability described in CVE-2008-4231 represents a critical memory corruption flaw within Apple's Safari web browser implementation on iOS devices. This issue affects iPhone OS versions 1.0 through 2.1 and iPod touch OS versions 1.1 through 2.1, exposing millions of devices to potential exploitation. The vulnerability specifically manifests when the browser encounters malformed HTML TABLE elements, creating a condition where improper memory handling leads to unpredictable behavior. The flaw falls under the category of buffer overflows and memory corruption vulnerabilities, which are classified as CWE-121 in the Common Weakness Enumeration framework. These types of vulnerabilities are particularly dangerous because they can be leveraged to execute arbitrary code or cause system instability.
The technical implementation of this vulnerability stems from Safari's insufficient validation and handling of malformed HTML table structures. When processing HTML documents containing specially crafted TABLE elements, the browser's rendering engine fails to properly manage memory allocation and deallocation processes. This improper memory management creates opportunities for attackers to manipulate memory contents through carefully constructed malicious HTML documents. The vulnerability operates at the intersection of web rendering and memory management, where the parser encounters unexpected table element structures that trigger memory corruption conditions. Attackers can exploit this by hosting malicious web content that, when loaded in Safari, causes the browser to allocate memory incorrectly, leading to memory overwrite conditions that can be leveraged for code execution.
The operational impact of this vulnerability extends beyond simple application crashes, presenting significant security risks to iOS users. Remote attackers can exploit this flaw to execute arbitrary code on affected devices, potentially gaining full system control or installing malicious software. The vulnerability also enables denial of service attacks that can render devices unusable through repeated application crashes. Users may encounter these attacks through malicious websites, phishing campaigns, or compromised web content that automatically loads when users browse the internet. The widespread adoption of iOS devices at the time meant that this vulnerability had a massive potential impact across a large user base, particularly given the popularity of Safari as the primary web browser on these platforms.
Mitigation strategies for this vulnerability required immediate system updates from Apple, as the flaw existed in the core browser rendering engine. Users needed to upgrade to patched versions of iOS to protect against exploitation, with Apple releasing security updates specifically addressing the memory corruption issues. Network administrators and security professionals should have implemented web content filtering measures to block suspicious HTML content and monitored for exploitation attempts. The vulnerability highlighted the importance of proper input validation in web browsers and reinforced the need for robust memory management practices in mobile operating systems. Organizations should have maintained updated threat intelligence feeds to identify potential exploitation attempts and implemented browser hardening measures to reduce attack surface. This vulnerability also emphasized the critical nature of mobile security and the need for comprehensive security testing of mobile browser implementations against various HTML parsing scenarios.