A buffer overflow vulnerability in the TCP/IP stack of Juniper Networks Junos OS allows an attacker to send specific sequences of packets to the device thereby causing a Denial of Service (DoS).

By repeatedly sending these sequences of packets to the device, an attacker can sustain the Denial of Service (DoS) condition.

The device will abnormally shut down as a result of these sent packets. A potential indicator of compromise will be the following message in the log files:

These issues are only triggered by traffic destined to the device. Transit traffic will not trigger these issues.

CVE-2021-0283 affects:

Juniper Networks Junos OS

• 12.3 versions prior to 12.3R12-S19;
• 15.1 versions prior to 15.1R7-S10;
• 16.1 version 16.1R1 and later versions;
• 16.2 version 16.2R1 and later versions;
• 17.1 version 17.1R1 and later versions;
• 17.2 version 17.2R1 and later versions;
• 17.3 versions prior to 17.3R3-S12;
• 17.4 version 17.4R1 and later versions;
• 18.1 versions prior to 18.1R3-S13;
• 18.2 version 18.2R1 and later versions;
• 18.3 versions prior to 18.3R3-S5;
• 18.4 versions prior to 18.4R2-S9, 18.4R3-S9;
• 19.1 versions prior to 19.1R3-S6;
• 19.2 versions prior to 19.2R1-S7, 19.2R3-S3;
• 19.3 versions prior to 19.3R2-S7, 19.3R3-S3;
• 19.4 versions prior to 19.4R3-S5;
• 20.1 versions prior to 20.1R2-S2, 20.1R3-S1;
• 20.2 versions prior to 20.2R3-S2;
• 20.3 versions prior to 20.3R3;
• 20.4 versions prior to 20.4R2-S1, 20.4R3;
• 21.1 versions prior to 21.1R1-S1, 21.1R2;
• 21.2 versions prior to 21.2R1-S1, 21.2R2.

CVE-2021-0284 affects:

Juniper Networks Junos OS

• 12.3 versions prior to 12.3R12-S19;
• 15.1 versions prior to 15.1R7-S10;
• 17.3 versions prior to 17.3R3-S12;
• 18.4 versions prior to 18.4R2-S9, 18.4R3-S9;
• 19.1 versions prior to 19.1R3-S7;
• 19.2 versions prior to 19.2R1-S7, 19.2R3-S3;
• 19.3 versions prior to 19.3R2-S7, 19.3R3-S3;
• 19.4 versions prior to 19.4R3-S5;
• 20.1 versions prior to 20.1R3-S1;
• 20.2 versions prior to 20.2R3-S2;
• 20.3 versions prior to 20.3R3-S1;
• 20.4 versions prior to 20.4R2-S2, 20.4R3;
• 21.1 versions prior to 21.1R2;
• 21.2 versions prior to 21.2R1-S1, 21.2R2.

CVE-2021-0283 was seen during production usage.

CVE-2021-0284 was found during internal product security testing or research.

Juniper SIRT is not aware of any malicious exploitation of either CVE-2021-0283 or CVE-2021-0284 vulnerabilities.

Juniper SIRT is aware of CVE-2021-0283 occurring in production. In all reported cases the Junos device was not the intended target of the attack, but this vulnerability was still triggered.

This issue was seen during production usage.

The following software releases have been updated to resolve both issues: Junos OS: 12.3R12-S19, 15.1R7-S10, 17.3R3-S12, 18.4R2-S9, 18.4R3-S9, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S7, 19.3R3-S3, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R2-S2, 20.4R3, 21.1R2, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.

The following software releases have been updated to resolve CVE-2021-0283: Junos OS: 12.3R12-S19, 15.1R7-S10, 17.3R3-S12, 18.1R3-S13, 18.3R3-S5, 18.4R2-S9, 18.4R3-S9, 19.1R3-S6, 19.2R1-S7, 19.2R3-S3, 19.3R2-S7, 19.3R3-S3, 19.4R3-S5, 20.1R2-S2, 20.1R3-S1, 20.2R3-S2, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.

The following software releases have been updated to resolve CVE-2021-0284: Junos OS: 12.3R12-S19, 15.1R7-S10, 17.3R3-S12, 18.4R2-S9, 18.4R3-S9, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S7, 19.3R3-S3, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R2-S2, 20.4R3, 21.1R2, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.

These issues are being tracked as  1557881  and  1595649 .
 

Software releases or updates are available for download at https://support.juniper.net/support/downloads/
 

There are no available workarounds for these issues.

To reduce the risk of exploitation of these issues, use access lists or firewall filters to limit access to the device to only trusted administrative networks, hosts and users.

2021-07-14: Initial Publication.
2021-07-21: Added additional versions to CVE-2021-0284 list in affected ranges and resolved-in.
2021-08-02: Added additional versions to CVE-2021-0284 list in affected ranges and resolved-in.
2021-08-17: Added additional versions to CVE-2021-0283, CVE-2021-0284, updated CVE detail text, product affected, problem and solution sections to reflect these changes along with minor typographical edits.
2021-10-27: Added additional versions to CVE-2021-0283, CVE-2021-0284.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0283: Junos OS: Upon receipt of specific sequences of genuine packets destined to the device the kernel will crash and restart (vmcore)
• CVE-2021-0284: **Reserved** at cve.mitre.org