#VU78261 Incomplete Internal State Distinction in Juniper Junos OS - CVE-2023-36834

Vulnerability identifier: #VU78261

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-36834

CWE-ID: CWE-372

Exploitation vector: Local 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 a denial of service (DoS) attack.

The vulnerability exists due to an error in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX 4600 and SRX 5000 Series. If an SRX is configured in L2 transparent mode the receipt of a specific genuine packet can cause a single Packet Processing Engines (PPE) component of the PFE to run into a loop, which in turn will render the PPE unavailable. Each packet will cause one PPE to get into a loop, leading to a gradual performance degradation until all PPEs are unavailable and all traffic processing stops.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Juniper Junos OS: 20.2R1-S1, 20.2R1-S2, 20.2R1-S3, 20.2R2-S1, 20.2R2-S2, 20.2R2-S3, 20.2R3-S1, 20.2R3-S2, 20.2R3-S3, 20.2R3-S4, 20.2R3-S5, 20.2R3-S6, 20.2, 20.2R1, 20.2R2, 20.2R3, 20.4R1-S1, 20.4R2-S1, 20.4R2-S2, 20.4R3-S1, 20.4R3-S2, 20.4R3-S3, 20.4R3-S4, 20.4R3-S5, 20.4R3-S6, 20.4, 20.4R1, 20.4R2, 20.4R3, 21.1R1-S1, 21.1R2-S1, 21.1R2-S2, 21.1R3-S1, 21.1R3-S2, 21.1R3-S3, 21.1R3-S4, 21.1, 21.1R1, 21.1R2, 21.1R3, 21.2R1-S1, 21.2R1-S2, 21.2R2-S1, 21.2R2-S2, 21.2R3-S1, 21.2R3-S2, 21.2R1, 21.2R2, 21.2R3, 21.3R1-S1, 21.3R1-S2, 21.3R2-S1, 21.3R2-S2, 21.3R3-S1, 21.3R3-S2, 21.3R1, 21.3R2, 21.3R3, 21.4R1-S1, 21.4R1-S2, 21.4R2-S1, 21.4R2-S2, 21.4R1, 21.4R2, 21.4R3, 22.1R1-S1, 22.1R1-S2, 22.1R2-S1, 22.1R2-S2, 22.1R1, 22.1R2, 22.2R1-S1, 22.2R1-S2, 22.2R1, 22.3R1

---

External links
https://supportportal.juniper.net/s/article/2023-07-Security-Bulletin-Junos-OS-SRX-4600-and-SRX-5000-Series-The-receipt-of-specific-genuine-packets-by-SRXes-configured-for-L2-transparency-will-cause-a-DoS-CVE-2023-36834

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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