CVE-2002-2308 in Communicator
Summary
by MITRE
Netscape Communicator 6.2.1 allows remote attackers to cause a denial of service in client browsers via a webpage containing a recursive META refresh tag where the content tag is blank and the URL tag references itself.
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Analysis
by VulDB Data Team • 06/12/2018
The vulnerability described in CVE-2002-2308 represents a classic example of a denial of service attack targeting web browser clients through malformed HTML content. This issue specifically affects Netscape Communicator 6.2.1, which was a widely used web browser in the early 2000s. The flaw manifests when a malicious webpage contains a recursive META refresh tag with empty content and self-referencing URL, creating an infinite loop that consumes system resources and ultimately crashes the browser. This type of vulnerability falls under the category of resource exhaustion attacks where the attacker leverages browser parsing behavior to consume memory and processing power without proper bounds checking or recursion limits.
The technical implementation of this vulnerability exploits the browser's handling of HTML meta refresh directives, which are used to automatically redirect users to another page after a specified time interval. In this case, the content attribute is left blank while the URL references the same page, creating a recursive refresh loop that the browser cannot properly terminate. The flaw demonstrates poor input validation and lack of recursion depth limits in the HTML parser component of Netscape Communicator 6.2.1. This vulnerability maps to CWE-121 which describes stack-based buffer overflow conditions, though in this instance the effect is more accurately characterized as a resource exhaustion issue. The recursive nature of the attack means that each refresh iteration consumes additional memory and CPU cycles, eventually leading to complete browser failure.
From an operational standpoint, this vulnerability presents significant risk to users who may encounter malicious web content while browsing the internet. The attack requires no special privileges or complex exploitation techniques, making it particularly dangerous as it can be triggered simply by visiting a compromised webpage. Users would experience immediate browser crashes, forcing them to restart their applications and potentially lose unsaved work. The impact extends beyond individual user experience to broader network security concerns, as this type of attack could be used in conjunction with other techniques to disrupt services or create distractions during more sophisticated attacks. This vulnerability also highlights the importance of proper browser sandboxing and input validation mechanisms that were still developing during this period of web browser evolution.
The mitigation strategies for this vulnerability primarily involve updating to patched versions of Netscape Communicator or upgrading to more modern browser implementations that properly handle recursive HTML constructs. Browser vendors should implement recursion depth limits in their HTML parsers and ensure proper bounds checking for meta refresh directives. Organizations should maintain updated browser software and implement web filtering solutions to block potentially malicious content. This vulnerability also reinforces the need for comprehensive web application security testing that includes edge cases involving malformed HTML content. The ATT&CK framework categorizes this under T1499 which covers network denial of service attacks, specifically highlighting how web-based applications can be manipulated to consume system resources. Additionally, the vulnerability demonstrates the importance of input sanitization and proper error handling in web browsers, which aligns with defensive programming principles and security best practices established in industry standards such as those defined by the Open Web Application Security Project.