f5 nginx CVE-2021-3618 vulnerability in F5 Networks and Other Products
Published on March 23, 2022

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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.

NVD

Weakness Type

Improper Certificate Validation

The software does not validate, or incorrectly validates, a certificate. When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.


Products Associated with CVE-2021-3618

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2021-3618 are published in these products:

F5 Networks Nginx
 
Sendmail
 
Vsftpdproject Vsftpd
 
Fedora Project Fedora
 
Canonical Ubuntu Linux
 
Debian Linux
 

Exploit Probability

EPSS
0.62%
Percentile
69.49%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.