Man-in-the-Middle (MitM) attack in gnutls (Alpine package)

Published: 2020-06-09

Risk	Medium
Patch available	YES
Number of vulnerabilities	1
CVE-ID	CVE-2020-13777
CWE-ID	CWE-300
Exploitation vector	Local network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software Subscribe	gnutls (Alpine package) Operating systems & Components / Operating system package or component
Vendor	Alpine Linux Development Team

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Man-in-the-Middle (MitM) attack

EUVDB-ID: #VU28557

Risk: Medium

CVSSv3.1: 5.5 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-13777

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform Man-in-the-Middle (MitM) attack.

The vulnerability exists due to regression, introduced into the TLS protocol implementation that caused the TLS server to not securely construct a session ticket encryption key considering the application supplied secret. A remote attacker can bypass authentication in TLS 1.3 and recover previous conversations in TLS 1.2

Mitigation

Install update from vendor's website.

Vulnerable software versions

gnutls (Alpine package): 3.6.6-r0 - 3.6.13-r1

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.