CVE-2017-3156 in CXF
Summary
by MITRE
The OAuth2 Hawk and JOSE MAC Validation code in Apache CXF prior to 3.0.13 and 3.1.x prior to 3.1.10 is not using a constant time MAC signature comparison algorithm which may be exploited by sophisticated timing attacks.
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Analysis
by VulDB Data Team • 08/29/2024
The vulnerability identified as CVE-2017-3156 affects Apache CXF versions prior to 3.0.13 and 3.1.x prior to 3.1.10, specifically within the OAuth2 Hawk and JOSE MAC Validation code. This issue represents a critical security flaw that undermines the integrity of authentication mechanisms by employing non-constant time algorithms for message authentication code verification. The vulnerability resides in the cryptographic implementation where the system fails to perform signature comparisons using constant-time operations, creating opportunities for attackers to exploit timing variations in the verification process.
The technical flaw manifests in the MAC (Message Authentication Code) validation routines that are used to verify the authenticity of OAuth2 Hawk and JOSE (JavaScript Object Signing and Encryption) tokens. When these systems perform signature comparisons, they use algorithms that exhibit different execution times depending on the input values, particularly when comparing MAC signatures. This timing variation occurs because the comparison process terminates early when differences are detected, allowing attackers to measure the time taken for verification and infer information about the correct signature. This timing-based side-channel attack technique directly violates the principles of constant-time cryptographic implementations.
The operational impact of this vulnerability is severe as it enables sophisticated attackers to perform timing attacks that can gradually reconstruct valid MAC signatures through repeated measurements of verification times. Attackers can leverage this weakness to bypass authentication mechanisms, potentially gaining unauthorized access to protected resources and services that rely on these validation routines. The vulnerability affects web services and applications that utilize Apache CXF for OAuth2 and JOSE implementations, making it particularly dangerous in enterprise environments where such frameworks are commonly deployed. The attack vector requires only the ability to make repeated requests to the vulnerable service and measure response times, making it accessible to moderately skilled adversaries.
Mitigation strategies for CVE-2017-3156 primarily involve upgrading to patched versions of Apache CXF, specifically version 3.0.13 or later for the 3.0.x series and 3.1.10 or later for the 3.1.x series. Organizations should also implement additional security controls including monitoring for unusual timing patterns in authentication requests and implementing rate limiting to prevent extensive timing attack attempts. The vulnerability aligns with CWE-203, which specifically addresses "Observable Timing Discrepancy" in cryptographic implementations, and relates to ATT&CK technique T1214, "Credentials in Files," as attackers may use timing attacks to extract authentication credentials. Security teams should also consider implementing proper cryptographic libraries that guarantee constant-time operations for all signature verification processes, ensuring that all authentication code paths execute in consistent time regardless of input values.