CVE-2019-5754 in Chrome
Summary
by MITRE
Implementation error in QUIC Networking in Google Chrome prior to 72.0.3626.81 allowed an attacker running or able to cause use of a proxy server to obtain cleartext of transport encryption via malicious network proxy.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability CVE-2019-5754 represents a critical implementation flaw in Google Chrome's QUIC networking protocol implementation that existed prior to version 72.0.3626.81. This issue specifically affects the handling of transport layer security within the QUIC protocol stack, which is designed to provide secure, low-latency communication between clients and servers. The flaw manifests when Chrome processes network requests through proxy servers, creating a scenario where sensitive transport encryption data can be exposed to malicious actors. The vulnerability operates at the intersection of network protocol implementation and security architecture, making it particularly dangerous in environments where proxy infrastructure is commonly deployed.
The technical root cause of this vulnerability stems from improper handling of QUIC protocol parameters during proxy connections, specifically in how Chrome manages the encryption handshake process when intermediate proxy servers are present. When a user connects through a proxy server, the QUIC implementation fails to properly isolate or protect certain encryption-related metadata that should remain confidential during the transport layer communication. This implementation error allows attackers who control or can influence proxy server behavior to extract cleartext information that should normally be protected by transport layer encryption. The flaw essentially creates a pathway for man-in-the-middle attacks where proxy-based network interception can reveal information that should remain encrypted, violating fundamental security assumptions of the QUIC protocol.
The operational impact of CVE-2019-5754 extends beyond simple data exposure, as it fundamentally undermines the security guarantees that QUIC is designed to provide. Attackers with access to or influence over proxy infrastructure can leverage this vulnerability to obtain sensitive information including session identifiers, cryptographic parameters, and potentially even application-layer data that should remain protected. This vulnerability affects users who rely on proxy servers for network access, which includes enterprise environments, educational institutions, and any network configuration that routes traffic through intermediate proxies. The risk is particularly elevated in scenarios where users connect through public or untrusted proxy networks, as these environments provide attackers with multiple opportunities to exploit the vulnerability. According to CWE-254, this represents a weakness in the security implementation that allows for information exposure, while ATT&CK technique T1071.002 highlights the exploitation of application layer protocols for data exfiltration.
Mitigation strategies for CVE-2019-5754 require immediate patching of Chrome installations to version 72.0.3626.81 or later, which contains the corrected QUIC implementation. Organizations should also implement network monitoring to detect unusual proxy behavior that might indicate exploitation attempts, and consider deploying additional security controls such as network segmentation or direct connections where possible. Security teams should review their proxy server configurations and ensure proper certificate validation is enforced, while also monitoring for any unauthorized proxy configurations that might expose users to this vulnerability. The fix addresses the core implementation error by properly isolating encryption parameters during proxy connections, ensuring that transport layer security remains intact regardless of network routing through intermediate proxy servers. This vulnerability demonstrates the critical importance of thorough testing and validation of security implementations, particularly in complex networking protocols where multiple layers of security must interoperate correctly.