CVE-2025-24895

SAML Response Signature Verification Bypass in CIE.AspNetCore.Authentication

Published Feb 18, 2025 CVSS 3.1 · 9.1 Critical EPSS < 1% KEV · Not listed

Description

CIE.AspNetCore.Authentication is an AspNetCore Remote Authenticator for CIE 3.0. Authentication using Spid and CIE is based on the SAML2 standard which provides two entities: 1. Identity Provider (IDP): the system that authenticates users and provides identity information (SAML affirmation) to the Service Provider, in essence, is responsible for the management of the credentials and identity of users; 2. Service Provider (SP): the system that provides a service to the user and relies on the Identity Provider to authenticate the user, receives SAML assertions from the IdP to grant access to resources. The library cie-aspnetcore refers to the second entity, the SP, and implements the validation logic of SAML assertions within SAML responses. In affected versions there is no guarantee that the first signature refers to the root object, it follows that if an attacker injects an item signed as the first element, all other signatures will not be verified. The only requirement is to have an XML element legitimately signed by the IdP, a condition that is easily met using the IdP's public metadata. An attacker could create an arbitrary SAML response that would be accepted by SPs using vulnerable SDKs, allowing him to impersonate any Spid and/or CIE user. This issue has been addressed in version 2.1.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

italia

cie-aspnetcore

affected

Version	Status	Constraints
`< 2.1.0`	affected	—

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2025-4791	CIE.AspNetCore.Authentication is an AspNetCore Remote Authenticator for CIE 3.0. Authentication using Spid and CIE is based on the SAML2 standard which provides two entities: 1. Identity Provider (IDP): the system that authenticates users and provides identity information (SAML affirmation) to the Service Provider, in essence, is responsible for the management of the credentials and identity of users; 2. Service Provider (SP): the system that provides a service to the user and relies on the Identity Provider to authenticate the user, receives SAML assertions from the IdP to grant access to resources. The library cie-aspnetcore refers to the second entity, the SP, and implements the validation logic of SAML assertions within SAML responses. In affected versions there is no guarantee that the first signature refers to the root object, it follows that if an attacker injects an item signed as the first element, all other signatures will not be verified. The only requirement is to have an XML element legitimately signed by the IdP, a condition that is easily met using the IdP's public metadata. An attacker could create an arbitrary SAML response that would be accepted by SPs using vulnerable SDKs, allowing him to impersonate any Spid and/or CIE user. This issue has been addressed in version 2.1.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Github GHSA	GHSA-vq63-8f72-f486	AspNetCore Remote Authenticator for CIE3.0 Allows SAML Response Signature Verification Bypass

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.607% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/italia/cie-aspnetcore/security/advisories/GHSA-vq63-8f72-f486

History

Feb 18, 2025 8:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Feb 18, 2025 7:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		CIE.AspNetCore.Authentication is an AspNetCore Remote Authenticator for CIE 3.0. Authentication using Spid and CIE is based on the SAML2 standard which provides two entities: 1. Identity Provider (IDP): the system that authenticates users and provides identity information (SAML affirmation) to the Service Provider, in essence, is responsible for the management of the credentials and identity of users; 2. Service Provider (SP): the system that provides a service to the user and relies on the Identity Provider to authenticate the user, receives SAML assertions from the IdP to grant access to resources. The library cie-aspnetcore refers to the second entity, the SP, and implements the validation logic of SAML assertions within SAML responses. In affected versions there is no guarantee that the first signature refers to the root object, it follows that if an attacker injects an item signed as the first element, all other signatures will not be verified. The only requirement is to have an XML element legitimately signed by the IdP, a condition that is easily met using the IdP's public metadata. An attacker could create an arbitrary SAML response that would be accepted by SPs using vulnerable SDKs, allowing him to impersonate any Spid and/or CIE user. This issue has been addressed in version 2.1.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.
Title		SAML Response Signature Verification Bypass in CIE.AspNetCore.Authentication
Weaknesses		CWE-287
References		https://github.com/italia/cie-aspnetcore/security/advisories/GHSA-vq63-8f72-f486
Metrics		cvssV3_1 `{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}`