NetSight
high7.4

CVE-2021-3618

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, su…

Impact

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 products

VendorProductAffected versions
F5Nginx
before 1.21.0
SendmailSendmail
before 8.17
Vsftpd ProjectVsftpd
before 3.0.4
FedoraprojectFedora
Versions 33, 34, 35
DebianDebian Linux
Version 10.0

Weakness classification

References