CVE-2023-46809 in Node.js (Bleichenbacher)
Summary
by MITRE • 09/07/2024
Node.js versions which bundle an unpatched version of OpenSSL or run against a dynamically linked version of OpenSSL which are unpatched are vulnerable to the Marvin Attack - https://people.redhat.com/~hkario/marvin/, if PCKS #1 v1.5 padding is allowed when performing RSA descryption using a private key.
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Analysis
by VulDB Data Team • 02/14/2025
The vulnerability identified as CVE-2023-46809 represents a critical security flaw in Node.js implementations that utilize OpenSSL for cryptographic operations. This vulnerability specifically targets the RSA decryption process when PKCS #1 v1.5 padding is permitted during private key operations, creating an exploitable condition that enables attackers to perform the Marvin Attack. The vulnerability stems from the improper handling of padding validation in RSA decryption routines, which allows for information leakage through timing variations and side-channel analysis. The affected Node.js versions either bundle an unpatched OpenSSL version or dynamically link against an unpatched OpenSSL library, making them susceptible to this sophisticated attack vector. The Marvin Attack, named after its discoverer and detailed in research by Red Hat's Henriksen Kario, exploits the differences in execution time between successful and failed padding validation checks, enabling attackers to gradually recover the plaintext message through repeated decryption attempts.
The technical implementation of this vulnerability occurs at the cryptographic protocol level within Node.js's OpenSSL integration, specifically in how the system handles RSA private key operations with PKCS #1 v1.5 padding. When Node.js processes RSA decryption requests using private keys, it performs padding validation checks that are not properly protected against timing side-channel attacks. The vulnerability manifests when the system allows PKCS #1 v1.5 padding to be used during RSA decryption, which creates predictable timing variations that can be measured and analyzed. This flaw falls under the CWE-327 weakness category, which deals with the use of weak cryptographic algorithms and improper implementation of cryptographic protocols. The vulnerability directly relates to the ATT&CK technique T1583.001, which involves the use of valid accounts and the exploitation of cryptographic weaknesses in system components. The OpenSSL library's implementation of RSA decryption operations fails to provide constant-time execution for padding validation, allowing attackers to gather sufficient information through statistical analysis to reconstruct the original message.
The operational impact of CVE-2023-46809 extends beyond simple information disclosure, as it can potentially lead to complete cryptographic key recovery and system compromise. Attackers can exploit this vulnerability to perform repeated decryption operations against target systems, gradually building statistical models that reveal the underlying plaintext data. The vulnerability affects any Node.js application that performs RSA decryption using private keys with PKCS #1 v1.5 padding, including web servers, API endpoints, and cryptographic service providers. Applications using Node.js versions that dynamically link to OpenSSL or bundle older OpenSSL versions are particularly vulnerable, as these configurations lack the necessary security patches that address the timing side-channel issues. The attack requires significant computational resources and time to execute successfully, but once completed, it can provide attackers with access to sensitive data that was previously protected by RSA encryption. This vulnerability represents a serious threat to applications handling confidential information, as it can be used to decrypt sensitive communications, access protected data, and potentially compromise authentication systems that rely on RSA encryption.
Mitigation strategies for CVE-2023-46809 must address both the immediate vulnerability and the underlying architectural issues that enable the attack. The primary recommendation involves upgrading Node.js to versions that either bundle patched OpenSSL libraries or dynamically link against properly patched OpenSSL versions that implement constant-time padding validation. Organizations should also consider implementing configuration changes that disable PKCS #1 v1.5 padding for RSA decryption operations and instead utilize newer padding schemes such as OAEP (Optimal Asymmetric Encryption Padding) which are designed to be resistant to timing attacks. System administrators should monitor their Node.js applications for usage of RSA private key operations and ensure that cryptographic libraries are regularly updated to prevent exploitation. Additional mitigations include implementing rate limiting for decryption operations, deploying intrusion detection systems that monitor for unusual cryptographic activity patterns, and conducting regular security assessments of Node.js applications that handle sensitive data. The vulnerability demonstrates the critical importance of maintaining up-to-date cryptographic libraries and implementing proper security controls in application environments that handle sensitive information. Organizations should also consider implementing automated patch management systems to ensure that OpenSSL and Node.js components are regularly updated with the latest security patches, preventing similar vulnerabilities from being exploited in the future.