Skip to content

Envoy incorrectly accepts HTTP 200 response for entering upgrade mode

Moderate
phlax published GHSA-vcf8-7238-v74c Jun 4, 2024

Package

source/common/router (Envoyproxy)

Affected versions

<1.30.2

Patched versions

1.30.2, 1.29.5, 1.28.4, 1.27.6

Description

Summary

A theoretical request smuggling vulnerability exists through Envoy if a server can be tricked into adding an upgrade header into a response.

Details

Per RFC https://www.rfc-editor.org/rfc/rfc7230#section-6.7 a server sends 101 when switching protocols.

Envoy incorrectly accepts a 200 response from a server when requesting a protocol upgrade, but 200 does not indicate protocol switch.

This opens up the possibility of request smuggling through Envoy if the server can be tricked into adding the upgrade header to the response.

Credits

reporter: [email protected]

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
Network
Attack complexity
High
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:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2024-23326

Weaknesses

Unchecked Error Condition

[PLANNED FOR DEPRECATION. SEE MAINTENANCE NOTES AND CONSIDER CWE-252, CWE-248, OR CWE-1069.] Ignoring exceptions and other error conditions may allow an attacker to induce unexpected behavior unnoticed. Learn more on MITRE.

Credits