2021-01 Security Bulletin: Junos OS: Command injection vulnerability in 'request system software' CLI command (CVE-2021-0219)

Product Affected:

This issue affects all versions of Junos OS.

Problem:

A command injection vulnerability in install package validation subsystem of Juniper Networks Junos OS that may allow a locally authenticated attacker with privileges to execute commands with root privilege. To validate a package in Junos before installation, an administrator executes the command 'request system software add validate-on-host' via the CLI. An attacker with access to this CLI command may be able to exploit this vulnerability.

This issue affects Juniper Networks Junos OS:

all versions prior to 17.3R3-S10;
17.4 versions prior to 17.4R2-S12, 17.4R3-S3;
18.1 versions prior to 18.1R3-S11;
18.2 versions prior to 18.2R2-S8, 18.2R3-S6;
18.3 versions prior to 18.3R3-S4;
18.4 versions prior to 18.4R1-S8, 18.4R2-S7, 18.4R3-S6;
19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S3;
19.2 versions prior to 19.2R3-S1;
19.3 versions prior to 19.3R2-S5, 19.3R3-S1;
19.4 versions prior to 19.4R2-S2, 19.4R3-S1;
20.1 versions prior to 20.1R2;
20.2 versions prior to 20.2R1-S2, 20.2R2;
20.3 versions prior to 20.3R1-S1, 20.3R2.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was discovered during external security research.

This issue has been assigned CVE-2021-0219.

Solution:

The following software releases have been updated to resolve this specific issue:

Junos OS: 17.3R3-S10, 17.4R2-S12, 17.4R3-S3, 18.1R3-S11, 18.2R2-S8, 18.2R3-S6, 18.2X75-D34, 18.3R3-S4, 18.4R1-S8, 18.4R2-S7, 18.4R3-S6, 19.1R1-S6, 19.1R2-S2, 19.1R3-S3, 19.2R3-S1, 19.3R2-S5, 19.3R3-S1, 19.4R2-S2, 19.4R3-S1, 20.1R2, 20.2R1-S2, 20.2R2, 20.3R1-S1, 20.3R2, 20.4R1, and all subsequent releases.

This issue is being tracked as 1519337.

Workaround:

Use access lists or firewall filters to limit CLI access to the device only from trusted, administrative networks or hosts.

Limit access to the Junos OS CLI to only trusted system administrators.

Restrict access to the 'request system software add validate-on-host' command.

Implementation:

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

Modification History:

2021-01-13: Initial Publication.

CVSS Score:

6.7 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H)

Severity Level:

Medium

Severity Assessment:

Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Acknowledgements:

Juniper SIRT would like to acknowledge and thank Hoàng Thạch Nguyễn (d4rkn3ss) of STAR Labs for responsibly reporting this vulnerability.

Knowledge Base