Red Hat Enterprise Linux 7 update for dovecot

1) Authentication bypass

EUVDB-ID: #VU17374

Risk: Medium

CVSSv4.0: 7.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:P/U:Green]

CVE-ID: CVE-2019-3814

CWE-ID: CWE-592 - Authentication Bypass Issues

Exploit availability: No

Description

The vulnerability allows a remote authenticated attacker to bypass authentication.

The weakness exists due to taking of the username from the user provided authentication fields (e.g. LOGIN command). A remote attacker with access to a valid trusted certificate without the ssl_cert_username_field in it can bypass password verification if the provided trusted SSL certificate is missing the username field and login as anyone else in the system

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power, little endian: 7

Red Hat Enterprise Linux for Power, big endian: 7

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

dovecot (Red Hat package): before 2.2.36-6.el7

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_big_endian:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_workstation:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:dovecot_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2020:1062

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

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.

2) Stack-based buffer overflow

EUVDB-ID: #VU18089

Risk: Low

CVSSv4.0: 7.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Clear]

CVE-ID: CVE-2019-7524

CWE-ID: CWE-121 - Stack-based buffer overflow

Exploit availability: No

Description

The vulnerability allows a local user to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when reading FTS or POP3-UIDL header from dovecot index. A local user can modify Dovecot index, trigger stack-based buffer overflow and execute arbitrary code on the target system with privileges of the Dovecot process.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power, little endian: 7

Red Hat Enterprise Linux for Power, big endian: 7

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

dovecot (Red Hat package): before 2.2.36-6.el7

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_big_endian:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_workstation:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server:7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:dovecot_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2020:1062

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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