Affected: ALPACA

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

Affected: Ubuntu:Pro:16.04:LTS: nginx, Ubuntu:18.04:LTS: nginx, Ubuntu:20.04:LTS: nginx

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to perform an HTTP Request Smuggling attack. This issue was fixed for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-11724)

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to disclose sensitive information. This issue only affects Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-36309)

It was discovered that nginx mishandled the use of compatible certificates among multiple encryption protocols. If a remote attacker were able to intercept the communication, this issue could be used to redirect traffic between subdomains. (CVE-2021-3618)