Why are system interfaces a special security problem?

Question

Accepted Answer

Interfaces are dangerous because two independently-built components have to interpret the exchanged data identically — and any mismatch in that interpretation is exploitable.
The core problem in three steps:

Step
What happens
Why it's dangerous

1. Independent development
Teams build components separately
No shared understanding of edge cases

2. Shared "language" at interface
Components exchange data using agreed format (SQL, HTTP, JSON...)
Format rules can be ambiguous or underspecified

3. Interpretation mismatch
Sender means "data", receiver interprets "code"
Attacker exploits the gap between intended and actual meaning

Tip: "Lost in translation" — security issues arise when systems don't "speak the same language" at interfaces.

Step	What happens	Why it's dangerous
1. Independent development	Teams build components separately	No shared understanding of edge cases
2. Shared "language" at interface	Components exchange data using agreed format (SQL, HTTP, JSON...)	Format rules can be ambiguous or underspecified
3. Interpretation mismatch	Sender means "data", receiver interprets "code"	Attacker exploits the gap between intended and actual meaning