CVE-2009-1233 in Safari
Summary
by MITRE
Apple Safari 3.2.2 and 4 Beta on Windows allows remote attackers to cause a denial of service (application crash) via an XML document containing many nested A elements.
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Analysis
by VulDB Data Team • 04/19/2025
The vulnerability identified as CVE-2009-1233 represents a classic denial of service flaw affecting Apple Safari web browsers on Windows platforms. This issue manifests when the browser encounters XML documents containing an excessive number of nested A elements, leading to application instability and potential crashes. The vulnerability specifically impacts Safari versions 3.2.2 and 4 Beta releases, highlighting a parsing weakness in how these browsers handle structured markup content. From a cybersecurity perspective, this represents a remote attack vector that requires no authentication or privileges from the attacker, making it particularly concerning for widespread exploitation. The flaw demonstrates how web browser rendering engines can be susceptible to malformed input that triggers memory management issues or stack overflow conditions during XML processing.
The technical mechanism behind this vulnerability involves the XML parser within Safari's rendering engine encountering deeply nested A elements that exceed the browser's parsing limits or memory allocation thresholds. When processing such malformed XML documents, the browser's XML parser may enter an infinite loop or exhaust available stack space, resulting in application termination. This behavior aligns with common software vulnerabilities categorized under CWE-121, which deals with stack-based buffer overflow conditions, and CWE-400, which addresses unspecified denial of service vulnerabilities. The vulnerability operates at the application layer of the network stack, classified as a remote attack that can be initiated through web content delivery without requiring any local system access or user interaction beyond visiting a malicious webpage.
The operational impact of CVE-2009-1233 extends beyond simple browser crashes, as it represents a potential vector for more sophisticated attacks within the broader context of the attacker's methodology. While the immediate effect appears to be a denial of service condition, such vulnerabilities often serve as stepping stones for more advanced exploitation techniques. The vulnerability's presence in Safari 4 Beta indicates that even pre-release software versions were susceptible to these parsing flaws, suggesting inadequate input validation and memory management in the browser's XML handling components. From an enterprise security standpoint, this vulnerability could be leveraged in targeted attacks against users who rely on Safari for web browsing, potentially disrupting business operations or serving as part of larger attack campaigns.
Security professionals should consider this vulnerability in relation to the broader ATT&CK framework, particularly under the T1499 category for network denial of service attacks. The vulnerability's exploitation requires no special privileges and can be executed through standard web browsing activities, making it a low-hanging fruit for threat actors seeking to disrupt services or establish initial access points. Organizations should implement immediate mitigations including browser updates, web content filtering, and network-based protections to prevent exploitation. The vulnerability also highlights the importance of proper input validation and memory management practices in browser development, aligning with industry standards that emphasize defensive programming techniques to prevent resource exhaustion attacks. Regular security assessments and patch management processes become critical in preventing such vulnerabilities from being exploited in real-world scenarios.