Identity spoofing attacks¶

Attack pattern¶

IPsec trusts a peer once IKE says the peer is who it claims, and that claim can be forged where the binding is weak. A pre-shared key used across many gateways proves membership, not identity; a certificate accepted without checking it truly belongs to this network address lets a valid cert stand in for the wrong host; a flexible set of identity formats gives room to present one thing and be treated as another. Convince IKE and the tunnel opens to the attacker as readily as to the real peer.

1. Identity spoofing [OR]

    1.1 Certificate identity spoofing [OR]

        1.1.1 Rogue certificate issuance [AND]
            1.1.1.1 Compromise CA private key
            1.1.1.2 Issue attacker-controlled certificates [AND]
                1.1.1.2.1 Sign certificates for arbitrary domains or peers
                1.1.1.2.2 Bypass victim trust checks

        1.1.2 Common Name (CN) spoofing [AND]
            1.1.2.1 Craft certificate CN to match target peer
            1.1.2.2 Use in TLS/IKE/IPsec handshake [AND]
                1.1.2.2.1 Victim accepts spoofed peer identity
                1.1.2.2.2 Enable man-in-the-middle or impersonation

        1.1.3 Subject Alternative Name (SAN) manipulation [AND]
            1.1.3.1 Insert attacker-controlled SAN entries
            1.1.3.2 Exploit victim certificate validation [AND]
                1.1.3.2.1 Match additional hostnames/IPs
                1.1.3.2.2 Facilitate multi-target impersonation

        1.1.4 Certificate validity period extension [AND]
            1.1.4.1 Exploit clock skew in victim system
            1.1.4.2 Present expired or future-dated certificate [AND]
                1.1.4.2.1 Bypass time-based certificate checks
                1.1.4.2.2 Extend window for impersonation attacks

        1.1.5 Intermediate CA injection [AND]
            1.1.5.1 Insert malicious intermediate CA into trust chain
            1.1.5.2 Sign certificates for arbitrary identities [AND]
                1.1.5.2.1 Exploit victim trust model
                1.1.5.2.2 Enable wide-scale spoofing without root compromise

    1.2 PSK identity manipulation [OR]

        1.2.1 Identity field tampering [AND]
            1.2.1.1 Modify IKE identity payloads
            1.2.1.2 Impersonate legitimate peer [AND]
                1.2.1.2.1 Exploit weak validation of peer ID
                1.2.1.2.2 Gain session establishment privileges

        1.2.2 PSK hash cracking [AND]
            1.2.2.1 Capture PSK handshake messages
            1.2.2.2 Compute pre-shared key from hashes [AND]
                1.2.2.2.1 Use brute force or dictionary attacks
                1.2.2.2.2 Recover PSK to impersonate peer

        1.2.3 Identity reflection attacks [AND]
            1.2.3.1 Exploit Aggressive Mode symmetry
            1.2.3.2 Reflect identity payloads back to victim [AND]
                1.2.3.2.1 Bypass authentication checks
                1.2.3.2.2 Facilitate man-in-the-middle

        1.2.4 Peer database enumeration [AND]
            1.2.4.1 Guess or probe identity fields
            1.2.4.2 Discover configured peers [AND]
                1.2.4.2.1 Use systematic trial identities
                1.2.4.2.2 Map victim configuration for targeted attacks

    1.3 IPv6 extension header identity abuse [OR]

        1.3.1 Routing header manipulation [AND]
            1.3.1.1 Craft IPv6 routing headers
            1.3.1.2 Spoof source addresses [AND]
                1.3.1.2.1 Bypass source-based identity checks
                1.3.1.2.2 Position attacker in MITM path

        1.3.2 Hop-by-hop option attacks [AND]
            1.3.2.1 Insert attacker-controlled hop options
            1.3.2.2 Evade identity verification [AND]
                1.3.2.2.1 Skip or confuse processing nodes
                1.3.2.2.2 Achieve stealthy traffic interception

        1.3.3 Destination option header spoofing [AND]
            1.3.3.1 Craft destination options to mislead peers
            1.3.3.2 Impersonate intended destination [AND]
                1.3.3.2.1 Enable targeted MITM attacks
                1.3.3.2.2 Exploit weak header validation

        1.3.4 Fragment header attacks [AND]
            1.3.4.1 Fragment IPv6 packets to bypass inspection
            1.3.4.2 Conceal spoofed identity [AND]
                1.3.4.2.1 Evade deep packet inspection
                1.3.4.2.2 Maintain session-level impersonation

Convince IKE, become the peer¶

PKI hierarchies and trust relationships are tangled enough to offer several routes to a forged identity.
Many implementations do not bind the cryptographic identity to the network identity, so a valid credential can front for the wrong host.
IKE accepts multiple identity types and formats, and the flexibility widens the surface.
IPv6 extension headers give extra room to obscure a true source.
Certificate policies and PSK management are often misconfigured.
Failed identity checks are frequently unlogged, so a spoofing attempt leaves little trace.