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SimpleSAMLphp Signature validation bypass

High severity GitHub Reviewed Published May 14, 2022 to the GitHub Advisory Database • Updated Apr 25, 2024

Package

composer simplesamlphp/simplesamlphp (Composer)

Affected versions

< 1.14.17

Patched versions

1.14.17

Description

A signature-validation bypass issue was discovered in SimpleSAMLphp through 1.14.16. A SimpleSAMLphp Service Provider using SAML 1.1 will regard as valid any unsigned SAML response containing more than one signed assertion, provided that the signature of at least one of the assertions is valid. Attributes contained in all the assertions received will be merged and the entityID of the first assertion received will be used, allowing an attacker to impersonate any user of any IdP given an assertion signed by the targeted IdP.

References

Published by the National Vulnerability Database Feb 2, 2018
Published to the GitHub Advisory Database May 14, 2022
Reviewed Apr 25, 2024
Last updated Apr 25, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.242%
(63rd percentile)

Weaknesses

CVE ID

CVE-2017-18122

GHSA ID

GHSA-j4qf-3w33-8cgc

Source code

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