samlify: XML Injection in AttributeValue Allows Privilege Escalation in Signed SAML Assertions

samlify is a Node.js library for SAML single sign-on. Prior to version 2.13.0, samlify’s template substitution only escapes attribute contexts. Values inserted into element text (e.g., <saml:AttributeValue>) are not escaped. A normal user can inject XML markup into an attribute value (e.g., email, name) and add new <saml:Attribute> elements inside the signed assertion. The IdP then signs the tampered assertion and the SP accepts the injected attributes as trusted. This allows privilege escalation when attributes are used for authorization (roles/groups). This issue has been patched in version 2.13.0.

samlify SAML Signature Wrapping attack

samlify is a Node.js library for SAML single sign-on. A Signature Wrapping attack has been found in samlify prior to version 2.10.0, allowing an attacker to forge a SAML Response to authenticate as any user. An attacker would need a signed XML document by the identity provider. Version 2.10.0 fixes the issue.

An XML Signature Wrapping vulnerability exists in Samlify 2.2.0 and earlier, and in predecessor Express-saml2 which could allow attackers to impersonate arbitrary users.