Firewall rules bypass in Junos OS on EX4300

1) Incorrect behavior order

EUVDB-ID: #VU88488

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2024-30410

CWE-ID: CWE-696 - Incorrect Behavior Order

Exploit availability: No

Description

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

The vulnerability exists due to an incorrect behavior order error in the routing engine (RE) of Juniper Networks Junos OS on EX4300 Series, which allows traffic intended to the device to reach the RE instead. A remote attacker can send specially crafted IPv6 packets to the device and bypass implemented firewall rules.

Note, the vulnerability affects only EX4300 switch.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Juniper Junos OS: 20.4R1-S1 - 21.4R3-S5

CPE2.3

• cpe:2.3:o:juniper_networks:juniper_junos_os:20.4R3-S9:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:21.2R3-S6:*:*:*:*:*:*:*
• cpe:2.3:o:juniper_networks:juniper_junos_os:21.4R3-S5:*:*:*:*:*:*:*

External links

https://supportportal.juniper.net/s/article/2024-04-Security-Bulletin-Junos-OS-EX4300-Series-Loopback-filter-not-blocking-traffic-despite-having-discard-term-CVE-2024-30410

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.