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CVE-2021-3618

Public on 2022-03-23
Modified on 2024-01-09
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.

Severity
Medium
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CVSS v3 Base Score
7.4
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Affected Packages

Platform Package Release Date Advisory
Amazon Linux 2 - Nginx1 Extra nginx 2023-08-07 06:17 ALAS2NGINX1-2023-002
Amazon Linux 2023 nginx 2023-02-17 20:48 ALAS2023-2023-099
Amazon Linux 2023 sendmail 2023-02-17 20:43 ALAS2023-2023-018
Amazon Linux 2 - Core vsftpd 2024-01-19 01:51 ALAS2-2024-2431
Amazon Linux 2023 vsftpd 2023-02-17 20:43 ALAS2023-2023-019

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD CVSSv2 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N
NVD CVSSv3 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Red Hat: CVE-2021-3618 Mitre: CVE-2021-3618 FAQs regarding Amazon Linux ALAS/CVE Severity