CVE-2009-1841 in Firefox
Summary
by MITRE
js/src/xpconnect/src/xpcwrappedjsclass.cpp in Mozilla Firefox before 3.0.11, Thunderbird before 2.0.0.22, and SeaMonkey before 1.1.17 allows remote attackers to execute arbitrary web script with the privileges of a chrome object, as demonstrated by the browser sidebar and the FeedWriter.
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Analysis
by VulDB Data Team • 08/11/2021
This vulnerability represents a critical privilege escalation flaw in the xpconnect component of mozilla firefox and related products. The issue resides in the xpcwrappedjsclass.cpp file which handles javascript to native code marshaling operations. Attackers can exploit this weakness to execute arbitrary web script with elevated chrome privileges, effectively bypassing security boundaries that normally protect privileged browser components. The vulnerability specifically affects versions prior to firefox 3.0.11 thunderbird 2.0.0.22 and seamonkey 1.1.17, making it particularly dangerous as these were widely deployed browser versions. The attack vector involves manipulating javascript execution contexts to gain access to chrome objects which normally operate with higher privileges than regular web content.
The technical implementation of this vulnerability stems from improper privilege checking within the xpconnect system that manages communication between javascript and native code components. When javascript code attempts to interact with chrome objects through wrapped javascript interfaces, the privilege validation mechanisms fail to properly verify the calling context. This allows malicious javascript running in untrusted web pages to indirectly access and manipulate privileged chrome objects through carefully crafted exploitation techniques. The vulnerability specifically manifests when the browser sidebar and feedwriter components are utilized, as these features have direct access to chrome objects and are particularly susceptible to this type of privilege escalation.
The operational impact of this vulnerability is severe as it enables attackers to execute arbitrary code with the privileges of the browser's chrome environment, which typically includes access to system resources, file system operations, and network communication capabilities. This means that an attacker could potentially read sensitive files, modify browser configuration, access user data, or even perform actions that would normally be restricted to privileged browser components. The attack demonstrates how a single flaw in the javascript to native code interface can provide a complete bypass of browser security boundaries, allowing full compromise of the user's browsing environment.
Mitigation strategies for this vulnerability require immediate patching of affected software versions to the patched releases that contain proper privilege validation checks. Organizations should prioritize updating firefox thunderbird and seamonkey installations to versions 3.0.11 2.0.0.22 and 1.1.17 respectively. Additionally implementing security measures such as content security policies and sandboxing configurations can help reduce the impact if exploitation occurs. This vulnerability aligns with CWE-276 which addresses improper privileges and also maps to ATT&CK technique T1059 which covers command and scripting interpreter usage. The fix implemented by mozilla involved strengthening the privilege validation logic in the xpconnect system to ensure that only appropriately authorized code can access chrome objects through javascript interfaces.