CVE-2009-4100 in Yoono
Summary
by MITRE
Yoono extension before 6.1.1 for Firefox performs certain operations with chrome privileges, which allows user-assisted remote attackers to execute arbitrary commands and perform cross-domain scripting attacks via DOM event handlers such as onload.
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Analysis
by VulDB Data Team • 01/23/2019
The vulnerability identified as CVE-2009-4100 represents a critical security flaw in the Yoono extension for Firefox browsers prior to version 6.1.1. This issue stems from the extension's improper handling of chrome privileges within its implementation, creating a significant attack surface that adversaries can exploit. The vulnerability specifically manifests when the extension performs certain operations with elevated chrome privileges, which are typically restricted to prevent malicious code execution from untrusted sources.
The technical exploitation of this vulnerability occurs through user-assisted remote attacks that leverage DOM event handlers, particularly the onload event. Attackers can craft malicious web content that triggers these event handlers, enabling the extension to execute arbitrary commands on the victim's system. This cross-domain scripting capability arises because the extension's chrome privilege operations do not properly enforce security boundaries between different domains, allowing malicious scripts to bypass normal browser security restrictions. The flaw essentially creates a privilege escalation path where untrusted web content can invoke privileged extension functions.
The operational impact of this vulnerability extends beyond simple script execution to encompass full system compromise potential. When successful, attackers can execute arbitrary code with the privileges of the browser extension, potentially leading to complete system infiltration. The cross-domain scripting aspect means that malicious actors can target users across different websites, making the attack vector particularly dangerous in environments where users browse multiple domains. This vulnerability undermines fundamental browser security models by allowing extension code to execute with elevated privileges without proper validation of the calling context.
Mitigation strategies for this vulnerability should focus on immediate remediation through updating to Yoono extension version 6.1.1 or later, which addresses the privilege escalation issue. Security administrators should also implement browser security policies that restrict extension permissions and monitor for suspicious extension behavior. The vulnerability aligns with CWE-276, which addresses improper privileges, and maps to ATT&CK technique T1059.007 for command and scripting interpreter. Organizations should conduct thorough security assessments of browser extensions to identify similar privilege escalation vulnerabilities, as this type of flaw represents a common attack pattern in browser-based exploitation. The incident underscores the critical importance of proper privilege management in browser extensions and the necessity of robust input validation when handling DOM events.