CVE-2021-3618

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 victims 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.

Weakness

The product does not validate, or incorrectly validates, a certificate.

Affected Software

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/459.html
• https://cwe.mitre.org/data/definitions/475.html

References

• https://alpaca-attack.com/
• https://bugzilla.redhat.com/show_bug.cgi?id=1975623
• https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html