CVE-2009-2955 in Chrome
Summary
by MITRE
Google Chrome 1.0.154.48 and earlier allows remote attackers to cause a denial of service (CPU consumption and application hang) via JavaScript code with a long string value for the hash property (aka location.hash), a related issue to CVE-2008-5715.
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Analysis
by VulDB Data Team • 11/22/2018
The vulnerability described in CVE-2009-2955 represents a significant denial of service flaw affecting Google Chrome versions 1.0.154.48 and earlier. This issue specifically targets the browser's handling of JavaScript code that manipulates the hash property of the location object, creating a scenario where malicious actors can exploit the browser's processing capabilities to consume excessive CPU resources and cause application hangs. The vulnerability operates through a straightforward yet effective mechanism that leverages the browser's JavaScript engine to process extremely long string values within the location.hash property.
The technical flaw stems from insufficient input validation and processing limitations within Chrome's JavaScript implementation. When a JavaScript program sets the hash property to a very long string value, the browser's internal processing mechanisms become overwhelmed, leading to excessive CPU consumption and eventual application freeze. This behavior occurs because the browser's hash property handling routine does not properly implement bounds checking or resource limiting for string length parameters. The vulnerability is particularly concerning as it can be triggered through standard web page scripting without requiring any special privileges or user interaction beyond visiting a malicious website.
From an operational perspective, this vulnerability creates a substantial risk for users of affected Chrome versions as it enables remote attackers to perform denial of service attacks against target systems. The attack requires minimal sophistication since it can be executed through standard JavaScript code that any web page can include, making it particularly dangerous in phishing campaigns or malicious websites. The resource exhaustion effects can render the browser completely unresponsive, forcing users to manually terminate the application or restart their system. This type of vulnerability directly impacts user productivity and can be exploited in targeted attacks against specific individuals or organizations where sustained browser unavailability would cause significant disruption.
The vulnerability aligns with CWE-400, which catalogs weaknesses related to uncontrolled resource consumption, and demonstrates how improper input handling can lead to system instability. From an attacker's perspective, this issue maps to ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a client-side exploitation vector that can be easily weaponized. The flaw also connects to broader security principles around input sanitization and resource management in web browsers. Organizations should implement immediate mitigations including updating to Chrome versions that address this vulnerability, deploying web application firewalls that can detect and block suspicious JavaScript patterns, and educating users about the risks of visiting untrusted websites. Additionally, browser security teams should consider implementing automatic resource limiting for JavaScript string operations and enhancing input validation mechanisms to prevent similar issues in future implementations.