CVE-2020-11767 Information disclosure in n/a
Attackers can intercept sensitive data via connection reuse in Istio or Envoy when SNI mismatches occur, bypassing browser domain isolation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2020-11767?
CVE-2020-11767 is a low-severity vulnerability in Envoyproxy Envoy, published on 15 Apr 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2020-11767?
1 open source package ship an affected version, including envoy. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
envoy Bitnami | All versions | 1.14.2 |
Products include Envoyproxy Envoy, Istio Istio.
How do I fix CVE-2020-11767?
Upgrade envoy to 1.14.2 or later.
Is CVE-2020-11767 being exploited?
There is no known exploitation of CVE-2020-11767 in the wild and no public exploit code.
Other vulnerabilities in Envoyproxy Envoy
Sources
Also known as BIT-envoy-2020-11767, GHSA-hvwr-mw2m-chj3.