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Prometheus Exporter-Toolkit is vulnerable to authentication bypass

Moderate severity GitHub Reviewed Published Nov 29, 2022 in prometheus/exporter-toolkit • Updated Jan 23, 2024

Package

gomod github.com/prometheus/exporter-toolkit (Go)

Affected versions

>= 0.8.0, < 0.8.2
< 0.7.2

Patched versions

0.8.2
0.7.2

Description

Impact

Prometheus and its exporters can be secured by a web.yml file that specifies usernames and hashed passwords for basic authentication.

Passwords are hashed with bcrypt, which means that even if you have access to the hash, it is very hard to find the original password back.

However, a flaw in the way this mechanism was implemented in the exporter toolkit makes it possible with people who know the hashed password to authenticate against Prometheus.

A request can be forged by an attacker to poison the internal cache used to cache the computation of hashes and make subsequent requests successful. This cache is used in both happy and unhappy scenarios in order to limit side channel attacks that could tell an attacker if a user is present in the file or not.

Patches

The exporter-toolkit v0.7.3 and v0.8.2 have been released to address this issue.

Workarounds

There is no workaround but attacker must have access to the hashed password, stored in disk, to bypass the authentication.

Credit

We want to thank Lei Wan reporting this security issue.

References

@roidelapluie roidelapluie published to prometheus/exporter-toolkit Nov 29, 2022
Published by the National Vulnerability Database Nov 29, 2022
Published to the GitHub Advisory Database Dec 2, 2022
Reviewed Dec 2, 2022
Last updated Jan 23, 2024

Severity

Moderate

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
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
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:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS score

1.200%
(86th percentile)

Weaknesses

CVE ID

CVE-2022-46146

GHSA ID

GHSA-7rg2-cxvp-9p7p

Source code

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