MitM attack in Fetchmail

1) Inadequate Encryption Strength

EUVDB-ID: #VU57578

Risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-39272

CWE-ID: CWE-326 - Inadequate Encryption Strength

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to Fetchmail before 6.4.22 fails to enforce STARTTLS session encryption in some circumstances, such as a certain situation with IMAP and PREAUTH. A remote attacker with ability to intercept network traffic can gain access to sensitive information.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Fetchmail: 6.4.0 - 6.4.21

External links

http://nostarttls.secvuln.info/
http://www.openwall.com/lists/oss-security/2021/08/27/3
http://www.fetchmail.info/security.html
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L3XJ6XLEJCEZCAM5LGGD6XBCC522QLG4/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZYCYLL73NP7ALJWSDICIVSA47ZIXWSSA/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VXMKSEHAQSEDCWZMAOJEGX3P3JW6QY6H/

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website or open a file.

Is there known malware, which exploits this vulnerability?

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