MitM attack in Samba Rsync

1) Improper validation of certificate with host mismatch

EUVDB-ID: #VU49239

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-14387

CWE-ID: CWE-297 - Improper Validation of Certificate with Host Mismatch

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists in Samba rsync due to the application does not verify the hostname in the server certificate in openssl mode. A remote attacker can supply any valid certificate for another hostname and intercept the traffic.

Mitigation

Vulnerable software versions

Rsync: 3.2.0 - 3.2.3pre1

CPE2.3

• cpe:2.3:a:samba:rsync:3.2.0:*:*:*:*:*:*:*
• cpe:2.3:a:samba:rsync:3.2.0pre1:*:*:*:*:*:*:*
• cpe:2.3:a:samba:rsync:3.2.0pre2:*:*:*:*:*:*:*

External links

https://bugzilla.redhat.com/show_bug.cgi?id=1875549
https://git.samba.org/?p=rsync.git;a=commitdiff;h=c3f7414c450faaf6a8281cc4a4403529aeb7d859
https://bugs.archlinux.org/task/69051

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.