Red Hat Enterprise Linux 7.5 Extended Update Support update for bind

1) Allocation of Resources Without Limits or Throttling

EUVDB-ID: #VU32025

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-5743

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

By design, BIND is intended to limit the number of TCP clients that can be connected at any given time. The number of allowed connections is a tunable parameter which, if unset, defaults to a conservative value for most servers. Unfortunately, the code which was intended to limit the number of simultaneous connections contained an error which could be exploited to grow the number of simultaneous connections beyond this limit. Versions affected: BIND 9.9.0 -> 9.10.8-P1, 9.11.0 -> 9.11.6, 9.12.0 -> 9.12.4, 9.14.0. BIND 9 Supported Preview Edition versions 9.9.3-S1 -> 9.11.5-S3, and 9.11.5-S5. Versions 9.13.0 -> 9.13.7 of the 9.13 development branch are also affected. Versions prior to BIND 9.9.0 have not been evaluated for vulnerability to CVE-2018-5743.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.5

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.5

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.5

Red Hat Enterprise Linux Server - Extended Update Support: 7.5

Red Hat Enterprise Linux EUS Compute Node: 7.5

bind (Red Hat package): before 9.9.4-61.el7_5.2

External links

http://access.redhat.com/errata/RHSA-2019:2977

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.