CVE-2017-18016 in Parity
Summary
by MITRE
Parity Browser 1.6.10 and earlier allows remote attackers to bypass the Same Origin Policy and obtain sensitive information by requesting other websites via the Parity web proxy engine (reusing the current website's token, which is not bound to an origin).
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Analysis
by VulDB Data Team • 06/22/2025
The vulnerability identified as CVE-2017-18016 affects Parity Browser versions 1.6.10 and earlier, presenting a critical security flaw that undermines fundamental web security mechanisms. This issue resides within the browser's web proxy engine implementation, specifically in how it handles cross-origin requests and token management. The vulnerability enables remote attackers to bypass the Same Origin Policy, a cornerstone security mechanism that prevents web pages from accessing resources from different origins without proper authorization. The flaw manifests when the browser's proxy engine reuses tokens across different origins without proper origin binding, creating a significant attack vector for information disclosure.
The technical implementation of this vulnerability stems from improper token handling within the Parity Browser's proxy architecture. When a user navigates to a website and the browser makes subsequent requests through its proxy engine, the system fails to properly validate or bind authentication tokens to specific origins. This allows an attacker to construct malicious requests that leverage existing tokens from one origin to access resources from another origin, effectively circumventing the browser's security boundaries. The vulnerability specifically exploits the lack of origin validation in the token management system, enabling unauthorized access to sensitive information that should be restricted to specific domains.
The operational impact of CVE-2017-18016 extends beyond simple information disclosure, potentially enabling more sophisticated attacks including session hijacking, cross-site request forgery, and data exfiltration. Attackers can leverage this vulnerability to access sensitive user data, session cookies, and other authenticated resources from different origins without proper authorization. The implications are particularly severe in environments where users access multiple web applications or services through the same browser instance, as the vulnerability creates persistent attack vectors that can be exploited across various domains and services. This weakness essentially transforms the browser's security model from a per-origin isolation system into a potentially compromised shared environment.
Security mitigations for this vulnerability should focus on implementing proper token origin binding and strengthening the proxy engine's validation mechanisms. Organizations should immediately update to Parity Browser versions that address this issue, as the vulnerability affects core browser functionality and cannot be effectively mitigated through configuration changes alone. The fix typically involves implementing origin-specific token validation, ensuring that authentication tokens are properly bound to their originating domain and cannot be reused across different origins. From a cybersecurity perspective, this vulnerability aligns with CWE-346, which addresses "Improper Verification of Source of a Communication Channel", and represents a significant concern under the ATT&CK framework's privilege escalation and credential access domains. The vulnerability demonstrates how proxy-based architectures can introduce security weaknesses when proper origin validation is not implemented, highlighting the importance of comprehensive security testing for browser components that handle cross-origin communications.