CVE-2015-2718 in Firefox
Summary
by MITRE
The WebChannel.jsm module in Mozilla Firefox before 38.0 allows remote attackers to bypass the Same Origin Policy and obtain sensitive webchannel-response data via a crafted web site containing an IFRAME element referencing a different web site that is intended to read this data.
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Analysis
by VulDB Data Team • 05/17/2022
The vulnerability identified as CVE-2015-2718 represents a critical security flaw in Mozilla Firefox's WebChannel.jsm module that existed prior to version 38.0. This issue fundamentally undermines the browser's core security mechanism known as the Same Origin Policy, which serves as the primary defense against cross-site scripting attacks and unauthorized data access. The vulnerability specifically affects the web channel implementation that allows communication between Firefox extensions and web content, creating an unexpected pathway for malicious actors to circumvent browser security boundaries.
The technical exploitation of this vulnerability occurs through a sophisticated cross-site scripting attack vector that leverages IFRAME elements to establish unauthorized data access. Attackers can craft malicious websites that embed IFRAMEs pointing to legitimate sites that contain sensitive webchannel-response data. The WebChannel.jsm module fails to properly validate the origin of requests, allowing a malicious page to intercept and extract data that should remain isolated within its intended domain context. This flaw operates at the intersection of browser security architecture and web communication protocols, exploiting the trust relationship between different domains within the same browser session.
The operational impact of this vulnerability extends far beyond simple data theft, as it enables sophisticated attacks that can compromise user privacy and potentially lead to identity theft or financial fraud. When successful, attackers can access sensitive information that includes but is not limited to user credentials, personal data, session tokens, and other confidential communications that should be protected by the same origin policy. The vulnerability is particularly dangerous because it operates silently in the background, allowing attackers to harvest data without user awareness or intervention, making it an ideal vector for persistent surveillance and data exfiltration campaigns.
Security researchers have classified this vulnerability under CWE-284, which addresses insufficient access control mechanisms, and it aligns with ATT&CK techniques related to privilege escalation and credential access through browser-based attacks. The flaw demonstrates how seemingly isolated security components can create cascading vulnerabilities when proper boundary enforcement is absent. Organizations and users affected by this vulnerability face significant risk as the attack requires no sophisticated tools or deep technical knowledge, making it accessible to threat actors of varying skill levels. The remediation process involves updating Firefox to version 38.0 or later, where the WebChannel.jsm module implements proper origin validation and access control measures that restore the integrity of the same origin policy enforcement.