CVE-2007-4812 in Safari
Summary
by MITRE
Buffer overflow in Apple Safari 3.0.3 522.15.5, and other versions before Beta Update 3.0.4, allows remote attackers to cause a denial of service (crash) and possibly have other unspecified impact by setting document.location.hash to a long string. NOTE: the crash might actually occur in the alert method.
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Analysis
by VulDB Data Team • 04/23/2019
The vulnerability identified as CVE-2007-4812 represents a critical buffer overflow flaw affecting Apple Safari web browser versions prior to Beta Update 3.0.4. This security weakness resides within the browser's handling of URL hash parameters and demonstrates how seemingly benign web interactions can lead to significant system instability. The vulnerability specifically manifests when the document.location.hash property receives an excessively long string input, triggering memory corruption that results in application crashes and potential system compromise. The flaw operates at the intersection of web browser architecture and memory management, where the browser's inability to properly validate input lengths leads to unauthorized memory access patterns.
The technical implementation of this vulnerability stems from inadequate bounds checking within Safari's JavaScript engine when processing hash values in URLs. When an attacker crafts a malicious URL containing an extraordinarily long hash string, the browser's internal buffer allocation fails to accommodate the excessive data, causing stack or heap corruption. This memory corruption typically manifests as a segmentation fault or access violation that terminates the browser process, resulting in denial of service conditions for the end user. The vulnerability's impact extends beyond simple crashes, as the underlying memory corruption could potentially be exploited for more sophisticated attacks depending on the execution environment and memory layout. The issue's classification aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, covering heap-based buffer overflow scenarios that may occur during dynamic memory allocation.
The operational implications of this vulnerability present significant risks to users who encounter malicious web content, particularly in environments where web browsing is essential for business operations. Attackers can exploit this weakness through various delivery mechanisms including malicious websites, phishing campaigns, or compromised web applications that redirect users to specially crafted URLs. The vulnerability's exploitation requires minimal user interaction beyond visiting a malicious website, making it particularly dangerous in real-world scenarios. Additionally, the fact that crashes may occur during alert method execution suggests that the vulnerability could be triggered through user interface elements that are commonly encountered during web browsing, potentially leading to more frequent exploitation opportunities. The timing of the vulnerability's occurrence during hash processing indicates that it affects all web content that relies on URL hash parameters, which are commonly used for bookmarking, navigation, and application state management.
Mitigation strategies for CVE-2007-4812 primarily focus on immediate software updates and browser configuration adjustments. The most effective solution involves upgrading to Safari Beta Update 3.0.4 or later versions where Apple has implemented proper bounds checking for hash parameter processing. Organizations should implement browser hardening measures including disabling JavaScript when possible, implementing content filtering solutions, and deploying web application firewalls that can detect and block malicious hash parameter patterns. Network-level protections such as intrusion detection systems can monitor for suspicious URL patterns that may indicate exploitation attempts. Users should be educated about the risks of visiting untrusted websites and the importance of keeping software updated. From an ATT&CK framework perspective, this vulnerability maps to technique T1211 which covers exploitation of known vulnerabilities, and T1059 which addresses execution through scripting languages. Security teams should also consider implementing runtime protections such as address space layout randomization and stack canaries to mitigate potential exploitation beyond the initial buffer overflow condition.