CVE-2020-11767

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

15/04/2020

Last modified:

21/07/2021

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&#39;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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 3.10 LOW
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): Low
Integrity (I): None
Availability (A): None

Base Score 3.x

3.10

Severity 3.x

LOW

Vector 2.0

AV:N/AC:H/Au:N/C:P/I:N/A:N CVSS v2.0 Severity and Metrics:

Base Score: 2.60 LOW
Vector: AV:N/AC:H/Au:N/C:P/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): None
Availability (A): None