CVE-2020-11767 Information

Description

Istio through 1.5.1 and Envoy through 1.14.1 have a data-leak issue. If there is a TCP connection (negotiated with SNI over HTTPS) to *.example.com a request for a domain concurrently configured explicitly (e.g. abc.example.com) is sent to the server(s) listening behind *.example.com. The outcome should instead be 421 Misdirected Request. Imagine a shared caching forward proxy re-using an HTTP/2 connection for a large subnet with many users. If a victim is interacting with abc.example.com and a server (for abc.example.com) recycles the TCP connection to the forward proxy the victim’s browser may suddenly start sending sensitive data to a *.example.com server. This occurs because the forward proxy between the victim and the origin server reuses connections (which obeys the specification) but neither Istio nor Envoy corrects this by sending a 421 error. Similarly this behavior voids the security model browsers have put in place between domains.

CVSS Vector

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

Reference

https://bugs.chromium.org/p/chromium/issues/detail?id=954160c5 https://github.com/envoyproxy/envoy/issues/6767 https://github.com/istio/istio/issues/13589 https://github.com/istio/istio/issues/9429

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

LOW

Availability Impact

NONE

Base Score

NONE

Base Severity

3.1