CVE-2021-21238 : Security Advisory and Response
Learn about CVE-2021-21238 impacting PySAML2 < 6.5.0. Includes details on the vulnerability, impact, affected systems, exploitation, and mitigation steps.
PySAML2 before version 6.5.0, a pure python implementation of SAML Version 2 Standard, is impacted by an improper verification of cryptographic signature vulnerability. This vulnerability affects users who validate signed SAML documents and can lead to XML Signature wrapping exploitation.
Understanding CVE-2021-21238
This CVE identifies a vulnerability in PySAML2 that allows for improper verification of cryptographic signatures, potentially exposing users to XML Signature wrapping attacks.
What is CVE-2021-21238?
PySAML2, a python implementation of SAML, is susceptible to a cryptographic signature verification flaw. Attackers can exploit this vulnerability through XML Signature wrapping, tricking the system with forged XML documents.
The Impact of CVE-2021-21238
The impact of this CVE is rated as medium, with a CVSS base score of 6.5. It can lead to a high integrity impact, but confidentiality is not affected. The attack complexity is low, requiring network access and user interaction.
Technical Details of CVE-2021-21238
PySAML2 version < 6.5.0 is vulnerable to improper cryptographic signature verification, allowing for XML Signature wrapping attacks.
Vulnerability Description
The vulnerability arises from the lack of proper validation of cryptographic signatures in SAML documents, enabling malicious actors to exploit the XML Signature wrapping weakness.
Affected Systems and Versions
PySAML2 versions prior to 6.5.0 are affected by this vulnerability, impacting all users who validate signed SAML documents.
Exploitation Mechanism
Attackers can exploit this vulnerability by crafting invalid XML documents with wrapped signatures, deceiving PySAML2 without proper schema validation.
Mitigation and Prevention
To address CVE-2021-21238, immediate action is required to ensure system security and integrity.
Immediate Steps to Take
Users should upgrade PySAML2 to version 6.5.0 or later to prevent exploitation of this vulnerability. Additionally, validating all SAML documents against XML schemas can help mitigate the risk of XML Signature wrapping attacks.
Long-Term Security Practices
Implementing secure coding practices and regular security audits can enhance overall system security and resilience against similar vulnerabilities.
Patching and Updates
Regularly check for security patches and updates from the PySAML2 project to stay protected against emerging threats.