whitehat-security/workplans/WHITEHAT-WP-0001-cross-tenant-evidence.md

---
id: WHITEHAT-WP-0001
type: workplan
title: "Produce the adversarial evidence the Tenancy Posture ladders require"
domain: infotech
repo: whitehat-security
status: proposed
owner: the-custodian
topic_slug: whitehat-security
created: "2026-08-17"
updated: "2026-08-17"
---

# WHITEHAT-WP-0001 — cross-tenant evidence

## Goal

Produce, on a schedule, the adversarial evidence artifacts that NetKingdom's
*Tenancy Posture* standard requires and no repo can honestly produce about
itself — starting with the one the framework calls its highest-severity gap.

Done means: a service claiming `E2` has been attacked as an adversary holding
its runtime credential, the attempt is recorded with a date and an attacker
model, and a failure routes to `risk-nexus` rather than to a log nobody reads.

## The forcing case

*Tenancy Posture* open question 3 has been unowned since the framework was
drafted. What it calls a tenant-boundary failure the security industry calls
**Broken Object Level Authorization** — OWASP API1, top of the API Security Top
10 since that list launched, and the most commonly exploited API vulnerability
in published assessments.

The estate has no coverage for it. `rapp-postgres` runs fifteen adversarial
probes and every one targets the *consumer* boundary — service versus service.
None targets the tenant boundary *inside* a consumer, which is where the
framework says the residual risk actually lives.

## Rules of engagement — T01, and nothing else starts first

An automated facility that probes systems without written scope is
indistinguishable from the threat it models. This is the gating task and it is
not paperwork.

- **Scope.** Which systems, which namespaces, which credentials. Explicitly:
  build-mode environments now; production requires a separate, recorded
  authorization.
- **Prohibited actions**, stated as hard rules rather than intentions:
  no destructive operations against data the estate did not create for the
  test; no exfiltration of real tenant data even as proof of a finding —
  a count and a schema shape are proof enough; no denial-of-service against a
  shared substrate outside a declared window, because the connection ceiling
  means a saturation probe is an outage for every co-resident.
- **Credentials.** The facility holds leased credentials like any workload,
  through the sanctioned OpenBao lane. It gets no standing privilege, and
  notably **no `BYPASSRLS` and no superuser** — an attacker would not have them
  and a probe holding them proves nothing.
- **Attribution.** Every probe connection is identifiable as a probe in
  `pg_stat_activity` and in logs, so an operator investigating an anomaly can
  tell us from a real adversary in seconds.
- **Abort.** How a run is stopped, by whom, and what state it leaves behind.

**Output:** `docs/rules-of-engagement.md`, reviewed by the operator personally.
This is exactly the class of thing `risk-nexus`'s escalation duty exists for.

## Tasks

### T01 — Rules of engagement
As above. Gates everything.

### T02 — The attacker model per axis

What the adversary is assumed to hold, so a probe is judged against a threat
rather than against taste. Drawn from *Tenancy Posture* §4.3, which already
distinguishes them:

| Axis | Adversary holds | Probe answers |
|---|---|---|
| E1/E2 | A legitimate runtime credential and the ability to make ordinary requests as tenant A | Can it reach tenant B's rows? |
| E3 | The above, plus SQL execution on the connection | Can it re-`SET` the tenant GUC and read across? |
| E4 | A leaked per-tenant credential | Can it address another tenant's substrate at all? |
| P1/P2 | A co-resident consumer behaving badly within its own allowance | What degradation do neighbours experience? |
| R | A copy of a backup taken before an erasure | Is the erased data still readable? |

**Output:** `docs/attacker-model.md`. Note that the E3 row exists because the
framework corrected itself: E3 stops accident, not compromise, and a probe that
only tested accident would report a strength E3 does not have.

### T03 — Differential cross-tenant harness (the E2 artifact)

The core technique: run the same request as two tenants and compare.

- Provision two disposable tenants against a target service.
- Exercise its surface as tenant A; attempt every object identifier observed
  from tenant B's context.
- Assert: B receives a denial or an empty result. **A well-formed 200
  containing A's data is the finding**, and the harness must be built to notice
  that rather than to notice errors — both of this estate's real regressions
  produced ordinary-looking responses, a 403 and a 404, and nothing alerted.
- Capture evidence as a count and a schema shape, never as tenant data (T01).

**Acceptance:** run against `tenant-engine` and `audit-core`, both of which
currently claim `E2`. The artifact is the run record, not a green tick.

### T04 — Prove the probes fail

A probe that has only ever passed is not evidence.

Build known-bad fixtures — a service with a deliberately missing tenant
predicate — and confirm each probe fails against them. `rapp-postgres` verified
its drift check this way, by re-pinning to a bad digest and confirming exit 1;
the same discipline applies here and is not optional.

**Acceptance:** every probe in T03 demonstrated failing before any of them is
trusted passing.

### T05 — RLS conformance under attack (the E3 artifact)

`rapp-postgres` ADR-0003 supplies an `rls_conformance` view and a template, and
states plainly that the platform's guarantee is **detection, not prevention** —
a table created by a later migration ships without a policy until something
notices. This repo is that something.

- Query the conformance view on a cadence; any row is a finding.
- Attack what the view cannot see: a session that sets no GUC must read
  nothing; a session with another tenant's value must see nothing; an insert
  attributed to another tenant must be refused.
- Attempt the documented bypasses: a `SECURITY DEFINER` function owned by the
  table owner, and a role holding `BYPASSRLS`.

**Cadence is the deliverable here, not a detail.** For a detection-based
control the interval between runs *is* the exposure window, and ADR-0003 leaves
the number to this repo. Set it, and state the resulting window in the record.

### T06 — Noisy-neighbour characterisation (the P1/P2 artifact)

The framework had to reword this artifact once already: its first draft
required proof that a saturating consumer "does not breach" another's
allowance, which shared infrastructure cannot provide.

What is achievable and therefore what this produces: a recorded baseline of
per-consumer resource usage; a run in which one consumer saturates its declared
allowance; evidence that the governance controls **bind**; and the degradation
co-residents experience, **measured and written down** rather than asserted
acceptable.

Runs inside a declared window per T01 — on a single-node rail with a six-
consumer connection ceiling, a saturation probe is an outage if run carelessly.

### T07 — Reporting into risk-nexus

Findings leave this repo in one direction. A run produces: what was attempted,
under which attacker model, when, against which posture claim, and the outcome.
It carries no severity — that is `risk-nexus`'s.

A **passing** run is also reported. "The attacks we thought of did not work" is
the honest claim, and recording it dated is what lets anyone see how stale the
assurance has become.

## Sequencing

T01 gates all. T02 shapes T03/T05/T06. T04 gates trusting any of them. T07 can
follow T03.

## Risks

**The facility becomes the threat.** Mitigated by T01, and by holding no
standing privilege.

**Probes weaken silently.** A probe that starts passing after a change to
itself rather than to the system is a finding, not a fix. Probe changes are
reviewed as security changes.

**Green is mistaken for safe.** Every report states that a pass means the
attacks attempted did not work, not that the boundary holds.

**It drifts into fixing things.** The boundary in INTENT is load-bearing:
findings route out, work does not come in.

## Open questions

1. **Owner confirmation.** Proposed `the-custodian`, deliberately not
   NetKingdom, whose framework this verifies. Needs the operator's yes.
2. **Where probes run from.** In-cluster gives realistic network position;
   outside gives independence from the substrate under test. Probably both,
   eventually; pick one to start.
3. **Does a service get told it is being probed?** Announced runs are easier to
   operate; unannounced ones test the alerting too. Build mode probably
   announced, production probably not — which is itself a T01 decision.