Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| F5 | Nginx | < 1.21.0 |
| Sendmail | Sendmail | < 8.17 |
| Vsftpd Project | Vsftpd | < 3.0.4 |
| Fedoraproject | Fedora | 33 |
| Debian | Debian Linux | 10.0 |
Related Weaknesses (CWE)
References
- https://alpaca-attack.com/Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1975623Issue TrackingPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/11/msg00031.htmlMailing ListThird Party Advisory
- https://alpaca-attack.com/Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1975623Issue TrackingPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/11/msg00031.htmlMailing ListThird Party Advisory
FAQ
What is CVE-2021-3618?
CVE-2021-3618 is a vulnerability with a CVSS score of 7.4 (HIGH). 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 certificat...
How severe is CVE-2021-3618?
CVE-2021-3618 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-3618?
Check the references section above for vendor advisories and patch information. Affected products include: F5 Nginx, Sendmail Sendmail, Vsftpd Project Vsftpd, Fedoraproject Fedora, Debian Debian Linux.