Vulnerability identifier: #VU57356

Vulnerability risk: Low

CVSSv3.1: 5.7 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-31366

CWE-ID: CWE-252

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Juniper Junos OS
Operating systems & Components / Operating system
MX Series
Hardware solutions / Firmware

Vendor: Juniper Networks, Inc.

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 - 15.1R7-S8, 17.3R1 - 17.3R3-S11, 17.4R1 - 17.4R3-S4, 17.4R2-S9, 18.1R1 - 18.1R3-S12, 18.2R1 - 18.2R3-S7, 18.3R1 - 18.3R3-S4, 18.3R3-S1, 18.3R2-S3, 18.4R1 - 18.4R3-S8, 18.4R2-S3, 18.4R1-S5, 19.1R - 19.1R3-S5, 19.1R1-S4, 19.2R1 - 19.2R3-S2, 19.2R1-S4, 19.3R1 - 19.3R3-S2, 19.3R2 - 19.3R2-S5, 19.3R1-S1, 19.4R2 - 19.4R3-S2, 19.4R1 - 19.4R1-S4, 20.1R1 - 20.1R2-S2, 20.2R1 - 20.2R3, 20.3R1 - 20.3R2-S1, 21.1R1 - 21.1R1-S1

MX Series: All versions

---

External links
http://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.