Product Affected

These issues affect all versions of Junos OS on SRX Series and EX Series.
Critical
9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Problem

An Out-of-bounds Write vulnerability in J-Web of Juniper Networks Junos OS SRX Series and EX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS), or Remote Code Execution (RCE) and obtain root privileges on the device.

This issue is caused by use of an insecure function allowing an attacker to overwrite arbitrary memory.

This issue affects Juniper Networks Junos OS SRX Series and EX Series:
Junos OS versions earlier than 20.4R3-S9;
Junos OS 21.2 versions earlier than 21.2R3-S7;
Junos OS 21.3 versions earlier than 21.3R3-S5;
Junos OS 21.4 versions earlier than 21.4R3-S5;
Junos OS 22.1 versions earlier than 22.1R3-S4;
Junos OS 22.2 versions earlier than 22.2R3-S3;
Junos OS 22.3 versions earlier than 22.3R3-S2;
Junos OS 22.4 versions earlier than 22.4R2-S2, 22.4R3.

The following minimal configuration must be present on the device:
[system services web-management http]
or
[system services web-management https]

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-2024-21591.
 

Solution

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

Junos OS: 20.4R3-S9, 21.2R3-S7, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S2, 22.4R2-S2, 22.4R3, 23.2R1-S1, 23.2R2, 23.4R1, and all subsequent releases.

This issue is being tracked as PR 1747984 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Workaround

Disable J-Web, or limit access to only trusted hosts.

Severity Assessment

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

Modification History

2024-01-10: Initial Publication

Related Information

CVSS v4.0 Score: 9.3 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)

Acknowledgements

The Juniper SIRT would like to would like to acknowledge and thanks Marco Lux of Curesec for responsibly reporting this vulnerability.