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.
https://bugzilla.redhat.com/show_bug.cgi?id=1975623
https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html
Source: MITRE
Published: 2022-03-23
Updated: 2023-02-09
Type: CWE-295
Base Score: 5.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:N
Impact Score: 4.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 7.4
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Impact Score: 5.2
Exploitability Score: 2.2
Severity: HIGH