CVE-2010-3773 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.5.16 and 3.6.x before 3.6.13, and SeaMonkey before 2.0.11, when the XMLHttpRequestSpy module in the Firebug add-on is used, does not properly handle interaction between the XMLHttpRequestSpy object and chrome privileged objects, which allows remote attackers to execute arbitrary JavaScript via a crafted HTTP response. NOTE: this vulnerability exists because of an incomplete fix for CVE-2010-0179.
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Analysis
by VulDB Data Team • 10/06/2021
The vulnerability described in CVE-2010-3773 represents a critical security flaw in Mozilla Firefox and SeaMonkey browsers that stems from improper handling of cross-origin object interactions within the Firebug add-on's XMLHttpRequestSpy module. This issue affects Firefox versions prior to 3.5.16 and 3.6.x prior to 3.6.13, as well as SeaMonkey versions before 2.0.11, creating a persistent threat vector that enables remote code execution through malicious HTTP responses. The vulnerability is particularly concerning because it exploits a complex interaction between privileged chrome objects and XMLHttpRequestSpy functionality, bypassing normal security boundaries that should prevent such cross-domain operations.
The technical root cause of this vulnerability lies in the incomplete remediation of CVE-2010-0179, which demonstrates how security fixes can sometimes create new attack surfaces when not thoroughly implemented. The XMLHttpRequestSpy module in Firebug is designed to monitor and inspect XMLHttpRequest operations, but when combined with chrome privileged objects, it creates a scenario where untrusted HTTP responses can manipulate privileged execution contexts. This flaw operates through a sandbox escape mechanism where the XMLHttpRequestSpy object fails to properly validate or isolate interactions with chrome objects, allowing attackers to inject malicious JavaScript code that executes with elevated privileges. The vulnerability specifically targets the object model interaction between the Firebug extension's monitoring capabilities and Firefox's core security architecture, creating a pathway for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a sophisticated attack vector that can be leveraged for complete browser compromise and potential system infiltration. Attackers can craft malicious HTTP responses that, when processed through the vulnerable XMLHttpRequestSpy module, trigger JavaScript execution within the browser's privileged context. This creates opportunities for data theft, session hijacking, and further exploitation of the compromised system. The vulnerability's persistence across multiple Firefox versions and the SeaMonkey browser underscores its significance in the broader security landscape, as it affects users who may not have immediately updated to patched versions. The incomplete fix for the previous CVE-2010-0179 demonstrates how security researchers must carefully consider the full scope of interactions when implementing fixes, as partial remediations can leave systems vulnerable to new attack vectors.
Security mitigation strategies for this vulnerability require immediate patching of affected browser versions, with particular attention to the Firebug add-on's XMLHttpRequestSpy functionality. Organizations should implement browser hardening measures that restrict or disable potentially dangerous add-ons, especially those with privileged access capabilities. The vulnerability aligns with CWE-284 (Improper Access Control) and CWE-94 (Improper Control of Generation of Code) categories, reflecting both access control failures and code execution vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 (Command and Scripting Interpreter: JavaScript) and T1071.004 (Application Layer Protocol: DNS) as attackers can leverage DNS responses to deliver malicious JavaScript payloads. System administrators should also consider implementing network-level protections such as web application firewalls and content filtering solutions to detect and block malicious HTTP responses that could exploit this vulnerability. The remediation process must include thorough testing of patched versions to ensure that the fix does not introduce regressions in legitimate functionality while maintaining the security boundary between privileged and unprivileged browser components.