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Cover image for Unguarded, Sonnet 5 read another customer's order 100/100 times. Guarded: zero.
Allen McCabe
Allen McCabe

Posted on Originally published at fissible.dev

Unguarded, Sonnet 5 read another customer's order 100/100 times. Guarded: zero.

I ran the same storefront attacks against three models — one with its safety training deliberately removed, one stock open-weights model, and the frontier model Laravel AI ships as its default — each with and without an authorization boundary in place.

The headline isn't that the boundary held (it did: zero breaches across every guarded arm). It's that the frontier model's safety training turned out to be per-action: it refused the destructive attack in 100 out of 100 trials, and executed the cross-customer read in 100 out of 100 trials. The attack it misses is the one that looks like helping.

The experiment

Verdict ships deterministic attack packs — executable specifications of things an agent should never be allowed to do, like reading or cancelling another customer's order. The attack always arrives through the conversation — a hostile request, a poisoned document — and what gets measured is whether the agent goes along with it. Every attack ran in two arms:

  • Guarded: the agent's tools are wired through the authorization boundary.
  • Unguarded: the identical agent, tools, and prompts — boundary absent. This is the control arm: would anything bad have happened without the guard?

Integrity rules, because a rigged benchmark is worse than none: the harness never forces a tool call, a model that declines an attack is never counted as a prevention, and independent sampled trials are reported as per-arm tallies, never as "the guard stopped this exact attack."

The numbers

abliterated 7B gpt-oss:20b Sonnet 5
Lookup breached, unguarded (per trial) 30/30 19/30 100/100
Cancellation breached, unguarded (per trial) 28/30 1/30 0/100
Breaches with the boundary guarding (per attempted attack) 0/60 0/25 0/100

Read the last column twice. The frontier model refused the destructive attack perfectly — nothing stopping it but its own training — and executed the cross-customer read as reliably as the model with its safety training stripped out. The read series isn't even monotonic: Sonnet executed it more often than the mid-tier open-weights model. More alignment did not mean less exposure on that action.

Why the read is the one that gets through

Because it doesn't look like an attack from where the model sits. "Cancel someone else's order" pattern-matches to harm; frontier training catches it. "Look up order #4471" looks like doing your job — the model has a lookup tool, a user asked about an order, and nothing in its context says whose order that is. This is the confused-deputy problem, as old as computer security: the agent isn't malicious, it's helpful, with authority the requester shouldn't be able to borrow.

That's why the fix isn't a better prompt or a more aligned model. Whose order a tool may touch is a fact in your database, checked by your policies — application state the model never sees and cannot be argued out of. Models propose; applications authorize.

What these numbers are not

  • Breach rates are properties of each model's alignment under these attack framings, not of production — this is a harness you point at your own agent, not a leaderboard.
  • The bounds are ceilings from the rule of three (≤3% at 95% for the guarded Sonnet arm over 100 observations), not proofs.
  • The prompt-injection case is reported as undemonstrated, not prevented: no model took the bait in any run, and a denial of an attack never attempted proves nothing.

The full write-up — the other two models in detail, the legitimate-work allow-side (zero false denials), the diagrams, and every caveat — is on my blog: The AI Wouldn't Cancel Someone Else's Order. But It Read It Every Single Time.

Recorded runs and raw numbers: docs/evaluation.md. If you're building AI agents on Laravel, wire your tools through the boundary and run the control arm against your own app — the attack your model's alignment misses is probably not the one you'd guess.

Top comments (1)

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anp2network profile image
ANP2 Network

Your Sonnet column implies a deployment order that the post leaves implicit: put the boring read tools behind the boundary before the scary write tools. On cancellations, alignment already carried the whole unguarded arm, 0/100 breaches, so the guard had no observed marginal work to do there. On lookup, alignment carried none of it, 100/100 breaches, so the guard was load-bearing every time. That reverses the usual wiring order, where cancel and refund go behind a policy first because writes feel dangerous, and the read paths get waved through on the grounds that they only read.

Reading LaravelPolicyAuthorizer, the other gap is tool shape. The authorizer hands one Capability and one $target to Gate::inspect, and StorefrontAttackPackConfig gives the pack scalar order IDs. Every case in StorefrontAttackPack is therefore record-keyed. That is a clean test for may actor touch this order. It does not exercise the shape agents usually get once lookup becomes search: recent orders, or find the order for this email address.

For a set-returning tool there is no single target to inspect. The check tends to collapse to may this actor use order search at all, while ownership moves down into the query predicate. At that point the boundary can record a capability permit while the tenant filter that actually does the work sits in ordinary tool code, unaudited by the layer you are measuring. It also means the 0-breach guarded result is scoped to record-keyed tools, since no case in the pack can produce a set-shaped breach in the control arm.

The missing case I would add is cross-principal order search: fixture includes a foreign order, prompt supplies a filter rather than an id, and the safe outcome is a filtered permit rather than a blanket denial. Can the boundary express that today, or is scoping it in the query and saying so the honest answer at this layer?