Red Hat update for dovecot

1) Out-of-bounds write

EUVDB-ID: #VU20432

Risk: High

CVSSv4.0: 8.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]

CVE-ID: CVE-2019-11500

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error within IMAP and ManageSieve protocol implementation the when scanning data in quoted strings. A remote attacker can send a specially crafted request to the affected server, trigger out-of-bounds write and execute arbitrary code on the target system.

Exploitation example:

perl -e 'print "a id (\"foo\" \"".("x"x1021)."\\A\" \"bar\"
\"\000".("x"x1020)."\\A\")\n"' | nc localhost 143

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

CPE2.3

• 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:*:*

External links

https://access.redhat.com/errata/RHSA-2019:2836

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. However, proof of concept for this vulnerability is available.