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 (term ) from/match application/application-set ] where either a. name = junos-sip or an application or application-set refers to SIP: b. [ applications application application-protocol sip ] or c. [ applications application-set 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.