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Firewall configured with unanimous strategy was not actually unanimous in Symfony

High severity GitHub Reviewed Published Mar 30, 2020 in symfony/symfony • Updated Feb 5, 2024

Package

composer symfony/security (Composer)

Affected versions

>= 4.4.0, < 4.4.7
>= 5.0.0, < 5.0.7

Patched versions

4.4.7
5.0.7
composer symfony/security-http (Composer)
>= 4.4.0, < 4.4.7
>= 5.0.0, < 5.0.7
4.4.7
5.0.7
composer symfony/symfony (Composer)
>= 4.4.0, < 4.4.7
>= 5.0.0, < 5.0.7
4.4.7
5.0.7

Description

Description

On Symfony before 4.4.0, when a Firewall checks an access control rule (using the unanimous strategy), it iterates over all rule attributes and grant access only if all calls to the accessDecisionManager decide to grant access.

As of Symfony 4.4.0, a bug was introduced that prevents the check of attributes as soon as accessDecisionManager decide to grant access on one attribute.

Resolution

The accessDecisionManager is now called with all attributes at once, allowing the unanimous strategy being applied on each attribute.

The patch for this issue is available here for the 4.4 branch.

Credits

I would like to thank Antonio J. García Lagar for reporting & Robin Chalas for fixing the issue.

References

@nicolas-grekas nicolas-grekas published to symfony/symfony Mar 30, 2020
Reviewed Mar 30, 2020
Published to the GitHub Advisory Database Mar 30, 2020
Last updated Feb 5, 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
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

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:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(51st percentile)

Weaknesses

Improper Authorization

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Learn more on MITRE.

CVE ID

CVE-2020-5275

GHSA ID

GHSA-g4m9-5hpf-hx72

Source code

No known source code

Credits

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