CVE-2011-2783 in Chrome
Summary
by MITRE
Google Chrome before 13.0.782.107 does not ensure that developer-mode NPAPI extension installations are confirmed by a browser dialog, which makes it easier for remote attackers to modify the product s functionality via a Trojan horse extension.
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Analysis
by VulDB Data Team • 11/15/2021
The vulnerability described in CVE-2011-2783 represents a critical security flaw in Google Chrome browser versions prior to 13.0.782.107 that undermines the browser's extension installation security model. This issue specifically affects the handling of NPAPI (Netscape Plugin Application Programming Interface) extensions, which are browser plugins that enable additional functionality through native code execution. The vulnerability stems from insufficient user confirmation mechanisms during the installation process of developer-mode extensions, creating a pathway for malicious actors to exploit the browser's trust model.
The technical flaw resides in Chrome's failure to implement proper user interaction requirements when installing NPAPI extensions in developer mode. Normally, when users attempt to install browser extensions, the browser should present a clear confirmation dialog that explicitly warns users about the installation and its potential implications. However, in affected versions, this confirmation step was bypassed for developer-mode extensions, allowing remote attackers to craft malicious Trojan horse extensions that could be silently installed without user awareness. This design oversight creates a privilege escalation vector where attackers can modify browser functionality without explicit user consent, potentially leading to persistent malware installation or unauthorized modification of browser behavior.
The operational impact of this vulnerability extends beyond simple extension installation, as it fundamentally compromises the browser's security architecture. Attackers can leverage this flaw to deploy malicious extensions that persist across browser sessions and potentially remain undetected by users. The vulnerability enables a range of malicious activities including but not limited to data exfiltration, browser manipulation, and the installation of additional malware components. From an attacker perspective, this represents a low-effort, high-impact vector since the attack can be executed remotely without requiring local system access or sophisticated social engineering techniques. The vulnerability is particularly concerning because it targets the browser's core extension management system, which serves as a critical entry point for third-party code execution.
Security practitioners should note that this vulnerability aligns with CWE-693, which addresses protection mechanism failures, specifically the inadequate protection of the extension installation process. The issue also relates to ATT&CK technique T1176, which covers the use of web shells and browser-based attacks to establish persistent access. Organizations should prioritize immediate patching of affected Chrome installations to address this vulnerability, as the window for exploitation was significant given the widespread use of older Chrome versions. Additionally, browser administrators should implement network monitoring to detect suspicious extension installation patterns and consider deploying extension whitelisting policies to further mitigate risk. The vulnerability demonstrates the importance of maintaining strict user confirmation requirements for all browser modifications, particularly those involving native code execution that can directly impact system security and user privacy.