xml-crypto vulnerable to XML signature verification bypass due improper verification of signature/signature spoofing
Date: 2024-05
Affected: npm/xml-crypto
Attack vector: other
Category: vulnerability-disclosure
Severity: Critical
CVE: CVE-2024-32962
CWE: CWE-347
CVSS: 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N)

### Summary Default configuration does not check authorization of the signer, it only checks the validity of the signature per section 3.2.2 of https://www.w3.org/TR/2008/REC-xmldsig-core-20080610/#sec-CoreValidation. As such, without additional validation steps, the default configuration allows a malicious actor to re-sign an XML document, place the certificate in a `<KeyInfo />` element, and pass `xml-crypto` default validation checks. ### Details Affected `xml-crypto` versions between versions `>= 4.0.0` and `< 6.0.0`. `xml-crypto` trusts by default any certificate provided via digitally signed XML document's `<KeyInfo />`. `xml-crypto` prefers to use any certificate provided via digitally signed XML document's `<KeyInfo />` even if library was configured to use specific certificate (`publicCert`) for signature verification purposes. Attacker can spoof signature verification by modifying XML document and replacing existing signature with signature generated with malicious private key (created by attacker) and by attaching that private key's certificate to `<KeyInfo />` element. Vulnerability is combination of changes introduced to `4.0.0` at * https://github.com/node-saml/xml-crypto/pull/301 * https://github.com/node-saml/xml-crypto/commit/c2b83f984049edb68ad1d7c6ad0739ec92af11ca Changes at PR provided default method to extract certificate from signed XML document. * https://github.com/node-saml/xml-crypto/blob/c2b83f984049edb68ad1d7c6ad0739ec92af11ca/lib/signed-x


Mitigations:

Architectural layers (MAESTRO):