MitM attack in Elastic Logstash

1) Improper Certificate Validation

EUVDB-ID: #VU51713

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-22138

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to improper TLS certificate validation in the monitoring feature of Logstash. When specifying a trusted server CA certificate Logstash does not properly verify the certificate returned by the monitoring server. A remote attacker can preform a Man-in-the-Middle attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Logstash: 6.4.0 - 7.11.2

CPE2.3

• cpe:2.3:a:elastic_stack:logstash:6.4.0:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.4.1:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.4.2:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.4.3:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.5.0:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.5.1:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.5.2:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.5.3:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.5.4:*:*:*:*:*:*:*
• cpe:2.3:a:elastic_stack:logstash:6.6.0:*:*:*:*:*:*:*

External links

https://www.elastic.co/community/security#ESA-2021-09

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.