title: Junos OS: SRX 5000 Series: Upon processing of a specific SIP packet an FPC can crash
description: An Improper Validation of Array Index vulnerability in the SIP ALG of Juniper Networks Junos OS on SRX 5000 Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). When an attacker sends an SIP packets with a malformed SDP field then the SIP ALG can not process it which will lead to an FPC crash and restart. Continued receipt of these specific packets will lead to a sustained Denial of Service. This issue can only occur when both below mentioned conditions are fulfilled: 1. Call distribution needs to be enabled: [security alg sip enable-call-distribution] 2. The SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. To confirm whether SIP ALG is enabled on SRX, and MX with SPC3 use the following command: user@host> show security alg status | match sip SIP : Enabled This issue affects Juniper Networks Junos OS on SRX 5000 Series: 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S4; 21.2 versions prior to 21.2R3-S3; 21.3 versions prior to 21.3R3-S3; 21.4 versions prior to 21.4R3-S2; 22.1 versions prior to 22.1R2-S2, 22.1R3; 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R1-S1, 22.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1.
problem types: CWE-129 Improper Validation of Array Index
affected:
{
vendor: Juniper Networks
product: Junos OS
versions:
version: unspecified, lessThan: 20.4R1, status: unaffected, versionType: custom
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
attackVector: NETWORK
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: NONE
integrityImpact: NONE
availabilityImpact: HIGH
baseScore: 7.5
baseSeverity: HIGH
]
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: The following software releases have been updated to resolve this specific issue: 20.4R3-S5, 21.1R3-S4, 21.2R3-S3, 21.3R3-S3, 21.4R3-S2, 22.1R2-S2, 22.1R3, 22.2R3, 22.3R1-S1, 22.3R2, 22.4R1, and all subsequent releases.
workarounds: There are no known workarounds for this issue, but it should be considered to disable the SIP call distribution if it's not strictly needed.