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Incorrect Authorization with specially crafted requests

High severity GitHub Reviewed Published Sep 9, 2021 in pomerium/pomerium • Updated Feb 1, 2023

Package

gomod github.com/pomerium/pomerium (Go)

Affected versions

>= 0.11.0, < 0.14.8
= 0.15.0

Patched versions

0.14.8
0.15.1

Description

Envoy, which Pomerium is based on, contains two authorization related vulnerabilities:

  • CVE-2021-32777: incorrectly transform a URL containing a #fragment element, causing a mismatch in path-prefix based authorization decisions.
  • CVE-2021-32779: incorrectly handle duplicate headers, dropping all but the last. This may lead to incorrect routing or authorization policy decisions.

Impact

With specially crafted requests, incorrect authorization or routing decisions may be made by Pomerium.

Patches

Pomerium v0.14.8 and v0.15.1 contain an upgraded envoy binary with these vulnerabilities patched.

Workarounds

  • This issue can only be triggered when using path prefix based policy. Removing any such policies should provide mitigation.

References

envoy GSA CVE-2021-32777
envoy GSA CVE-2021-32779
envoy announcement

For more information

If you have any questions or comments about this advisory:

References

@travisgroth travisgroth published to pomerium/pomerium Sep 9, 2021
Published by the National Vulnerability Database Sep 9, 2021
Reviewed Sep 10, 2021
Published to the GitHub Advisory Database Sep 10, 2021
Last updated Feb 1, 2023

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
None
User interaction
None
Scope
Changed
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:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS score

0.272%
(68th percentile)

Weaknesses

CVE ID

CVE-2021-39206

GHSA ID

GHSA-cfc2-wjcm-c8fm

Source code

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