CVE-2007-2869 in Firefox
Summary
by MITRE
The form autocomplete feature in Mozilla Firefox 1.5.x before 1.5.0.12, 2.x before 2.0.0.4, and possibly earlier versions, allows remote attackers to cause a denial of service (persistent temporary CPU consumption) via a large number of characters in a submitted form.
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Analysis
by VulDB Data Team • 07/20/2019
The vulnerability described in CVE-2007-2869 represents a significant denial of service weakness in Mozilla Firefox browser versions prior to specific patch releases. This issue specifically targets the form autocomplete functionality that users rely on for convenience when filling out web forms. The flaw manifests when attackers exploit the autocomplete feature by submitting forms containing an excessive number of characters, which triggers abnormal resource consumption patterns within the browser's processing mechanisms. The vulnerability operates at the application layer and demonstrates how seemingly benign user interface features can be weaponized for system disruption.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within Firefox's form handling subsystem. When the browser processes form submissions containing excessive character counts, the autocomplete algorithm fails to properly throttle or limit the processing of these inputs, leading to persistent temporary CPU consumption. This behavior creates a resource exhaustion condition where the browser's processing threads become overwhelmed with repetitive or excessive data handling operations. The vulnerability is classified under CWE-400 as an Uncontrolled Resource Consumption weakness, specifically manifesting as a denial of service through excessive CPU utilization.
From an operational perspective, this vulnerability presents a substantial risk to browser stability and user experience. Attackers can exploit this weakness to consume significant system resources, potentially causing the browser to become unresponsive or significantly slow down system performance. The persistent nature of the CPU consumption means that once triggered, the impact continues until the browser is restarted or the malicious form submission is processed. This type of attack aligns with ATT&CK technique T1499.004 for network denial of service attacks and demonstrates how browser-based vulnerabilities can be leveraged for system-level disruption.
The security implications extend beyond simple resource consumption, as this vulnerability could be combined with other attack vectors to create more sophisticated exploitation scenarios. The affected versions represent a critical window of exposure where users were vulnerable to persistent performance degradation attacks. Organizations and individuals using these browser versions faced ongoing risks of system instability and reduced productivity. The vulnerability highlights the importance of proper input sanitization and resource management in web browser implementations, particularly for features that process user-generated content. Effective mitigation requires updating to patched versions of Firefox, implementing network-level filtering for suspicious form submissions, and establishing monitoring protocols to detect unusual CPU consumption patterns. The remediation process involves both immediate patch deployment and long-term architectural improvements to prevent similar resource exhaustion scenarios in browser-based applications.