CVE-2009-3271 in iPhone OS
Summary
by MITRE
Apple Safari on iPhone OS 3.0.1 allows remote attackers to cause a denial of service (application crash) via a long tel: URL in the SRC attribute of an IFRAME element.
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Analysis
by VulDB Data Team • 12/14/2024
The vulnerability described in CVE-2009-3271 represents a classic buffer overflow condition that affects Apple Safari running on iPhone OS 3.0.1. This issue manifests when the browser encounters a maliciously crafted tel: URL within the src attribute of an iframe element, causing the application to crash and resulting in a denial of service condition. The flaw demonstrates the critical importance of proper input validation and boundary checking in mobile browser implementations, particularly when handling external references and protocol handlers.
Technical exploitation of this vulnerability occurs through the improper handling of excessively long telephone number URIs within iframe elements. When Safari processes such malformed input, the browser's parsing mechanism fails to properly validate the length of the tel: URI, leading to memory corruption that ultimately triggers an application crash. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which addresses stack-based buffer overflow scenarios. The vulnerability specifically impacts the browser's URL parsing and resource loading subsystems, where insufficient bounds checking allows malicious input to overwrite adjacent memory regions.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides attackers with a method to reliably crash Safari applications on iOS devices. Mobile users could be exposed to this attack through various vectors including malicious websites, phishing campaigns, or compromised web content that embeds the malicious iframe with the crafted tel: URI. The vulnerability affects the broader iOS ecosystem since iPhone OS 3.0.1 was widely deployed, potentially exposing millions of users to remote exploitation. This type of denial of service attack can be classified under ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a significant security gap in mobile browser security implementations.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through Apple's security updates, as well as implementing network-level protections such as web application firewalls that can detect and block malicious iframe content. Browser vendors should implement comprehensive input validation for all URI protocols, particularly those that can trigger system-level operations. The fix typically involves adding proper length validation and boundary checking mechanisms to prevent buffer overflows when processing tel: URIs and other protocol handlers within iframe elements. Organizations should also consider implementing mobile device management policies that enforce timely security updates and monitor for suspicious web content that might exploit similar vulnerabilities in other browser components.