Vulnerability identifier: #VU54915

Vulnerability risk: Medium

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-2021-0289

CWE-ID: CWE-367

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Juniper Junos OS
Operating systems & Components / Operating system

Vendor: Juniper Networks, Inc.

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to a race condition between the Device Control Daemon (DCD) and firewall process (dfwd) daemons of Juniper Networks Junos OS, when user-defined ARP Policer is configured and applied on one or more Aggregated Ethernet (AE) interface units. A remote attacker on the local network can bypass the user-defined ARP Policer.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Juniper Junos OS: 19.4 - 19.4R3-S3, 19.4R1 - 19.4R1-S4, 21.1 - 21.1R1-S1, 20.4 - 20.4R2-S2, 20.2 - 20.2R3-S1, 18.4 - 18.4R3-S8, 18.4R1-S5, 18.4R2-S3, 15.1 - 15.1R7-S9, 15.1F - 15.1F7-S2, 20.1 - 20.1R2-S2

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External links
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA11191&cat=SIRT_1&actp=LIST

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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.