When an active TCP connection transitions to LAST_ACK state and the daemon connected to the socket still has more data to send, the socket could get stuck in LAST_ACK state indefinitely, using up finite mbufs and connections. Triggering this condition repeatedly could lead to total mbuf exhaustion, requiring a reboot or switchover of the primary RE to resolve. Exploitation of this issue requires establishment of a TCP connection to a listening port on the router. TCP ports protected by ingress and/or control plane firewall filters are not vulnerable to this issue. However, anti-spoofing mechanisms should be employed to protect against malicious attempts to bypass existing firewall filters. Juniper SIRT is not aware of any malicious exploitation of this vulnerability. This issue has been assigned CVE-2015-5358 .
The following software releases have been updated to resolve this specific issue: Junos OS 12.1X44-D50, 12.1X46-D35, 12.1X47-D25, 12.3R9, 12.3X48-D15, 13.2R7, 13.2X51-D35, 13.2X52-D25, 13.3R6, 14.1R3-S2, 14.1R4, 14.1X53-D12, 14.1X53-D16, 14.1X55-D25, 14.2R2, 15.1R1, and all subsequent releases. This issue is being tracked as PR 1029758 and is visible on the Customer Support website. KB16765 [juniper.net] - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
Limit the exploitable attack surface of critical infrastructure networking equipment. Use access lists or firewall filters to limit access to the router via TCP only from trusted, administrative networks or hosts. Additionally, for BGP sessions, employ anti-spoofing mechanisms such as uRPF and TTL security mechanisms to protect against source address spoofing.
2015-07-08: Initial publication 2020-11-20: Updated terminology