Denial of service in Juniper Networks Junos OS on MX Series

1) Unchecked Return Value

EUVDB-ID: #VU57356

Risk: Low

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-31366

CWE-ID: CWE-252 - Unchecked Return Value

Exploit availability: No

Description

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

The vulnerability exists due to unchecked return value in the authd (authentication daemon). A remote attacker on the local network can send a specific username and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Juniper Junos OS: 15.1R - 21.1R1

MX Series: All versions

CPE2.3

• cpe:2.3:o:juniper_networks:juniper_junos_os:15.1R7:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:17.3R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:17.4R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:18.1R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:18.2R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:18.3R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:18.4R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:19.1R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:19.2R3:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:19.3R3:*:*:*:*:*:*:*
• cpe:2.3:h:juniper_networks:mx_series:*:*:*:*:*:*:*:*

External links

https://kb.juniper.net/InfoCenter/index?page=content&id=JSA11228&cat=SIRT_1&actp=LIST

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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