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 Details
- CVSS 3.1 Base Score: 7.4
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade nginx | Mar 26, 2024 | Mar 23, 2022 |
| Amazon Linux Ami 2 | — | Upgrade nginx-mod-mailUpgrade nginxUpgrade nginx-mod-http-image-filterUpgrade nginx-all-modulesUpgrade nginx-mod-http-perlUpgrade nginx-mod-http-geoipUpgrade vsftpd-sysvinitUpgrade nginx-filesystemUpgrade nginx-debuginfoUpgrade vsftpdUpgrade nginx-mod-http-xslt-filterUpgrade vsftpd-debuginfoUpgrade nginx-mod-stream | Sep 28, 2023 | Mar 23, 2022 |
| Amazon_linux_2023 | — | Upgrade nginx-mod-http-perlUpgrade nginx-mod-stream-debuginfoUpgrade nginx-debuginfoUpgrade nginx-debugsourceUpgrade nginx-mod-develUpgrade sendmail-milterUpgrade nginx-mod-streamUpgrade nginx-mod-http-image-filter-debuginfoUpgrade nginx-mod-http-xslt-filterUpgrade nginx-mod-http-image-filterUpgrade sendmail-milter-debuginfoUpgrade nginx-coreUpgrade sendmailUpgrade sendmail-cfUpgrade vsftpd-debuginfoUpgrade nginx-mod-mail-debuginfoUpgrade nginx-core-debuginfoUpgrade nginx-mod-http-perl-debuginfoUpgrade nginx-mod-mailUpgrade sendmail-debugsourceUpgrade vsftpd-debugsourceUpgrade nginx-filesystemUpgrade nginxUpgrade sendmail-debuginfoUpgrade nginx-mod-http-xslt-filter-debuginfoUpgrade sendmail-docUpgrade sendmail-milter-develUpgrade vsftpdUpgrade nginx-all-modules | Feb 17, 2025 | Jun 9, 2021 |
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | Mar 23, 2022 |
| Debian | — | Upgrade sendmailUpgrade nginxUpgrade vsftpd | Nov 24, 2022 | Mar 23, 2022 |
| Huawei Euleros 2_0_sp3 | — | Upgrade nginx | Oct 26, 2021 | Sep 24, 2021 |
| Huawei Euleros 2_0_sp5 | — | Upgrade nginx-mod-streamUpgrade nginx-mod-http-xslt-filterUpgrade nginx-filesystemUpgrade nginx-mod-mailUpgrade nginxUpgrade nginx-mod-http-perlUpgrade nginx-all-modulesUpgrade nginx-mod-http-image-filter | Sep 29, 2021 | Sep 24, 2021 |
| Huawei Euleros 2_0_sp8 | — | Upgrade nginx-mod-mailUpgrade nginx-all-modulesUpgrade nginx-mod-http-perlUpgrade nginx-mod-http-image-filterUpgrade nginxUpgrade nginx-filesystemUpgrade nginx-mod-streamUpgrade nginx-mod-http-xslt-filter | Sep 24, 2021 | Sep 24, 2021 |
| Nginx | — | Upgrade to nginx version 1.21.0 | Feb 10, 2023 | Mar 23, 2022 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Mar 23, 2022 |
| Suse | — | Upgrade vsftpdUpgrade vim-plugin-nginxUpgrade nginx-sourceUpgrade nginx | Oct 26, 2022 | Mar 23, 2022 |
| Ubuntu | — | Upgrade nginx-fullUpgrade vsftpdUpgrade nginx-core (Ubuntu Pro)Upgrade nginx-extras (Ubuntu Pro)Upgrade nginx-coreUpgrade nginx-light (Ubuntu Pro)Upgrade nginx-extrasUpgrade nginx-lightUpgrade libnginx-mod-http-lua | Apr 13, 2022 | Mar 23, 2022 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Mar 23, 2022 |
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