title: Junos OS: MX Series and SRX Series: When receiving a specific SIP packets stale call table entries are created which eventually leads to a DoS for all SIP traffic
description: An Improper Release of Memory Before Removing Last Reference vulnerability in the Session Initiation Protocol (SIP) Application Layer Gateway (ALG) of Juniper Networks Junos OS allows unauthenticated network-based attacker to cause a partial Denial of Service (DoS). On all MX and SRX platforms, if the SIP ALG is enabled, receipt of a specific SIP packet will create a stale SIP entry. Sustained receipt of such packets will cause the SIP call table to eventually fill up and cause a DoS for all SIP traffic. The SIP call usage can be monitored by "show security alg sip calls". To be affected the SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. Please verify on SRX with: user@host> show security alg status | match sip SIP : Enabled Please verify on MX whether the following is configured: [ services ... rule <rule-name> (term <term-name>) from/match application/application-set <name> ] where either a. name = junos-sip or an application or application-set refers to SIP: b. [ applications application <name> application-protocol sip ] or c. [ applications application-set <name> application junos-sip ] This issue affects Juniper Networks Junos OS on SRX Series and MX Series: 20.4 versions prior to 20.4R3-S2; 21.1 versions prior to 21.1R3-S2; 21.2 versions prior to 21.2R2-S2; 21.2 versions prior to 21.2R3; 21.3 versions prior to 21.3R2; 21.4 versions prior to 21.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 20.4R1. Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
problem types: CWE-401 Improper Release of Memory Before Removing Last Reference
affected:
{
platforms: SRX Series, MX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 20.4R1, status: unaffected, version: unspecified, versionType: custom
lessThan: 20.4R3-S2, status: affected, version: 20.4, versionType: custom
lessThan: 21.1R3-S2, status: affected, version: 21.1, versionType: custom
changes: [at: 21.2R3, status: unaffected], lessThan: 21.2R2-S2, status: affected, version: 21.2, versionType: custom
lessThan: 21.3R2, status: affected, version: 21.3, versionType: custom
lessThan: 21.4R2, status: affected, version: 21.4, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 5.3
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
version: 3.1
]
solutions: The following software releases have been updated to resolve this specific issue: 20.4R3-S2, 21.1R3-S2, 21.2R2-S2, 21.2R3, 21.3R2, 21.4R2, 22.1R1, and all subsequent releases.
workarounds: There are no known workarounds for this issue, but it should be considered to disable the SIP ALG if it's not strictly needed.