CVE-2017-1000433 in PySAML2
Summary
by MITRE
pysaml2 version 4.4.0 and older accept any password when run with python optimizations enabled. This allows attackers to log in as any user without knowing their password.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-1000433 affects the pysaml2 library version 4.4.0 and earlier, presenting a critical authentication bypass flaw that undermines the security of identity management systems relying on this component. This issue specifically manifests when the library operates under Python optimization settings, creating a condition where authentication mechanisms become completely ineffective regardless of the password provided during login attempts.
The technical root cause of this vulnerability stems from improper validation of authentication credentials within the pysaml2 library's authentication flow. When Python optimizations are enabled through the -O flag or similar optimization mechanisms, the library's password validation logic fails to properly verify user credentials, allowing any string input to be accepted as valid authentication. This represents a fundamental flaw in the authentication subsystem that directly violates security principle of least privilege and credential verification. The vulnerability operates at the application layer and can be classified under CWE-287, which deals with improper authentication mechanisms, specifically focusing on authentication bypass through improper validation of credentials.
The operational impact of this vulnerability is severe and far-reaching, particularly for organizations implementing SAML-based single sign-on solutions. Attackers exploiting this flaw can gain unauthorized access to any user account within the system without requiring legitimate credentials, effectively bypassing all authentication controls. This vulnerability transforms what should be a secure authentication process into a completely open system where privilege escalation becomes trivial. The implications extend beyond simple unauthorized access as attackers can potentially compromise entire user sessions, access sensitive data, and perform actions with full user privileges. The vulnerability affects systems where pysaml2 is used for authentication, particularly those implementing SAML identity providers or service providers that rely on this library for secure authentication flows.
Organizations affected by this vulnerability should immediately implement mitigations including updating to pysaml2 version 4.5.0 or later, which contains the necessary patches to address the authentication bypass issue. Additionally, administrators should disable Python optimizations for applications using this library until the upgrade is complete, as the vulnerability specifically requires optimization flags to be active. Security monitoring should be enhanced to detect unusual authentication patterns and login attempts that might indicate exploitation of this vulnerability. The mitigation strategy should also include implementing additional authentication controls such as multi-factor authentication, access logging, and regular security audits of authentication systems. From an ATT&CK framework perspective, this vulnerability maps to T1078 Valid Accounts and T1566 Phishing, as it allows attackers to leverage valid accounts through credential bypass techniques, and represents a technique that could be used in initial access phases of cyber attacks. The vulnerability also aligns with T1087 Account Discovery, as attackers could potentially enumerate valid accounts within the system once they have bypassed authentication. System administrators should conduct comprehensive vulnerability assessments to identify all systems using affected versions of pysaml2, and implement network segmentation to limit the potential impact of successful exploitation.