Vulnerability identifier: #VU52228

Vulnerability risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-0257

CWE-ID: CWE-401

Exploitation vector: 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 perform DoS attack on the target system.

The vulnerability exists due memory leak. On Juniper Networks MX Series and EX9200 Series platforms with Trio-based MPCs (Modular Port Concentrators) where Integrated Routing and Bridging (IRB) interfaces are configured and mapped to a VPLS instance or a Bridge-Domain, certain Layer 2 network events at Customer Edge (CE) devices may cause memory leaks in the MPC of Provider Edge (PE) devices which can cause an out of memory condition and MPC restart.

Mitigation

Install updates from vendor's website.

This issue affects:

Juniper Networks Junos OS on MX Series, EX9200 Series

• 17.3 versions prior to 17.3R3-S10;
• 17.4 versions prior to 17.4R3-S3;
• 18.2 versions prior to 18.2R3-S7;
• 18.3 versions prior to 18.3R3-S4;
• 18.4 versions prior to 18.4R3-S6;
• 19.2 versions prior to 19.2R3-S2;
• 19.3 versions prior to 19.3R3-S1;
• 19.4 versions prior to 19.4R2-S2, 19.4R3;
• 20.2 versions prior to 20.2R1-S3, 20.2R2;
• 20.3 versions prior to 20.3R1-S1,, 20.3R2.

This issue does not affect Juniper Networks Junos OS:

• 17.3 versions prior to 17.3R3-S8;
• 17.4 versions prior to 17.4R3-S2;
• any version of 18.1;
• 18.2 versions prior to 18.2R3-S4;
• 18.3 versions prior to 18.3R3-S2;
• 18.4 versions prior to 18.4R3-S1;
• any version of 19.1;
• 19.2 versions prior to 19.2R2;
• 19.3 versions prior to 19.3R3;
• 19.4 versions prior to 19.4R2.

Vulnerable software versions

Juniper Junos OS: 19.2 - 19.2R3-S1, 19.2R1-S4, 20.2 - 20.2R2-S3, 18.2 - 18.2R3-S6, 20.4, 20.3 - 20.3R1-S2, 18.3 - 18.3R3-S3, 18.3R2-S3, 18.3R3-S1, 19.3 - 19.3R3, 19.3R1-S1, 19.3R2 - 19.3R2-S7, 19.4 - 19.4R2-S8, 19.4R1 - 19.4R1-S4, 18.4 - 18.4R3-S5, 18.4R1-S5, 18.4R2-S3, 17.4 - 17.4R3-S2, 17.4R2-S9, 17.3 - 17.3R3-S9, 20.1 - 20.1R1-S4

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External links
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA11148&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 Internet.

Is there known malware, which exploits this vulnerability?

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