Resource exhaustion attacks¶

1. Resource exhaustion attacks [OR]

    1.1 SA table exhaustion attacks [OR]

        1.1.1 Rapid SA establishment from spoofed source addresses [AND]
            1.1.1.1 Generate multiple IKE_SA_INIT requests with forged IPs
            1.1.1.2 Force the IPsec stack to allocate SA entries [AND]
                1.1.1.2.1 Consume kernel or daemon memory
                1.1.1.2.2 Exhaust SA table capacity leading to denial-of-service

        1.1.2 Half-open SA state retention attacks [AND]
            1.1.2.1 Initiate SA setup without completing handshake
            1.1.2.2 Prevent proper garbage collection [AND]
                1.1.2.2.1 Keep ephemeral SAs alive in memory
                1.1.2.2.2 Exhaust resources and prevent new SA establishment

        1.1.3 SA rekeying storms to overwhelm state tables [AND]
            1.1.3.1 Trigger repeated rekey messages
            1.1.3.2 Exploit simultaneous child SA updates [AND]
                1.1.3.2.1 Saturate SA table processing
                1.1.3.2.2 Cause latency, failures, or crashes

        1.1.4 Persistent SA creation without proper teardown [AND]
            1.1.4.1 Exploit missing or delayed SA deletion
            1.1.4.2 Flood system with new SAs [AND]
                1.1.4.2.1 Consume memory and CPU
                1.1.4.2.2 Induce service denial

    1.2 IKE negotiation flood [OR]

        1.2.1 IKE_SA_INIT flooding with spoofed source IPs [AND]
            1.2.1.1 Send high-volume IKE_SA_INIT requests
            1.2.1.2 Force daemon to process incomplete negotiations [AND]
                1.2.1.2.1 Consume CPU cycles
                1.2.1.2.2 Prevent legitimate IKE establishment

        1.2.2 Resource-intensive transform attribute flooding [AND]
            1.2.2.1 Craft IKE messages with numerous transforms
            1.2.2.2 Force cryptographic processing [AND]
                1.2.2.2.1 Consume CPU for algorithm negotiation
                1.2.2.2.2 Increase memory allocation

        1.2.3 Large certificate payload attacks during IKE_AUTH [AND]
            1.2.3.1 Provide oversized or complex certificates
            1.2.3.2 Exploit certificate parsing routines [AND]
                1.2.3.2.1 Consume memory and processing resources
                1.2.3.2.2 Potentially trigger crashes

        1.2.4 Repeated failed negotiations to consume CPU cycles [AND]
            1.2.4.1 Send intentionally invalid IKE messages
            1.2.4.2 Force repeated validation/retry [AND]
                1.2.4.2.1 Exhaust CPU and memory
                1.2.4.2.2 Delay or block legitimate traffic

    1.3 CPU exhaustion through crypto processing [OR]

        1.3.1 Algorithm negotiation forcing computationally expensive ciphers [AND]
            1.3.1.1 Prioritise strong ciphers (AES-256, 3DES)
            1.3.1.2 Force repeated key schedule computations [AND]
                1.3.1.2.1 Consume CPU resources
                1.3.1.2.2 Slow legitimate sessions

        1.3.2 Large Diffie-Hellman group selection (groups 21, 24) [AND]
            1.3.2.1 Negotiate large modular exponentiations
            1.3.2.2 Force heavy math operations [AND]
                1.3.2.2.1 Consume CPU per handshake
                1.3.2.2.2 Amplify DoS potential via volume

        1.3.3 RSA encryption with large key sizes (4096-bit+) [AND]
            1.3.3.1 Negotiate large RSA keys during IKE/Auth
            1.3.3.2 Force CPU-intensive exponentiation [AND]
                1.3.3.2.1 Delay session setup
                1.3.3.2.2 Enable CPU-based DoS

        1.3.4 Perfect Forward Secrecy enforcement triggering frequent rekeying [AND]
            1.3.4.1 Initiate multiple ephemeral DH exchanges
            1.3.4.2 Exploit rekey policy frequency [AND]
                1.3.4.2.1 Consume CPU and entropy sources
                1.3.4.2.2 Slow or disrupt legitimate communications

    1.4 Memory exhaustion via large SAs [OR]

        1.4.1 Crafted SAs with excessive transform attributes [AND]
            1.4.1.1 Include many transforms in proposal
            1.4.1.2 Force allocation of large SA structures [AND]
                1.4.1.2.1 Consume kernel/daemon memory
                1.4.1.2.2 Reduce resources for legitimate SAs

        1.4.2 Large certificate chain consumption in IKE negotiations [AND]
            1.4.2.1 Supply multiple certificates per authentication
            1.4.2.2 Force parsing of oversized chains [AND]
                1.4.2.2.1 Exhaust memory
                1.4.2.2.2 Delay handshake completion

        1.4.3 Extended sequence number (ESN) state allocation attacks [AND]
            1.4.3.1 Trigger long sequence number tracking
            1.4.3.2 Allocate state for all possible windows [AND]
                1.4.3.2.1 Consume memory resources
                1.4.3.2.2 Prevent new SA establishment

        1.4.4 Anti-replay window expansion attacks [AND]
            1.4.4.1 Manipulate packet sequences to expand anti-replay buffers
            1.4.4.2 Force allocation of large sliding windows [AND]
                1.4.4.2.1 Exhaust memory
                1.4.4.2.2 Increase processing overhead