A Network Allow-List Won't Stop Exfiltration
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Security architecture insight, relevant to cloud infrastructure.
A network allow-list cannot stop data exfiltration because attackers can encode secrets in DNS subdomain lookups or HTTP requests to permitted domains. The Canister sandbox addresses this by forcing all outbound TCP through a local HTTPS proxy that performs TLS termination, inspects plaintext, and checks DNS entropy, using seccomp SECCOMP_USER_NOTIF to intercept connect() syscalls. This design is motivated by supply chain attacks like the Shai-Hulud worm that exfiltrated credentials via npm installs.
- Implement an egress proxy with TLS inspection and DNS entropy checks to detect data exfiltration through allowed channels.
For a solutions architect building secure CI/CD pipelines or sandboxed AI agent execution, this highlights a critical blind spot in network policies and a practical L7 DLP approach.