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Narnaiezzsshaa Truong
Narnaiezzsshaa Truong

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Adversarial Thinking Template: Working Backward from the Goal

Threat modeling, penetration testing, and security design all share
a core discipline: thinking like an adversary. But adversarial
thinking isn't limited to cybersecurity—it applies anywhere you need
to anticipate failure modes, identify weak points, or stress-test systems.

This is my preferred method: always work backward from the objective.
Whether you're an attacker seeking data exfiltration, a defender
hardening infrastructure, or a cook ensuring flawless flan, the
questions remain the same.

Here’s a structured adversarial thinking template you can use across domains—security, debugging, marketing, design, even recipes. It’s built around my preferred method: always work backward from the goal/objective.


Step 1: Define the Desired Outcome

  • What is the attacker’s (or evaluator’s) end state? (e.g., data theft, privilege escalation, flawless flan, successful campaign)
  • What must be true for this outcome to exist? (e.g., credentials compromised, custard set, audience converted)
  • What signals confirm success? (e.g., exfiltrated data, jiggle test, conversion metrics)

Step 2: Map Constraints and Affordances

  • Affordances: What the system naturally makes easy?
  • Constraints: What defenses or resistances exist?
  • Ambiguities: Where policy and reality diverge?

Step 3: Work Backward Pathways

  • Direct routes: Straightforward paths to the goal.
  • Side channels: Indirect or overlooked paths.
  • Combinatorics: Weak signals combined into strong outcomes.
  • Pivot nodes: Small wins that unlock larger reach.

Step 4: Identify Choke Points

  • Single points of failure: If broken, many paths collapse.
  • Silent success indicators: Signs you’re close without alarms.
  • Counterfactual probes: Actions that should change the system but don’t (revealing weak controls).

Step 5: Invert for Defense or Design

  • Label motifs: Name recurring vulnerabilities (“Orphaned Authority,” “Ambient Secrets”).
  • Publish refusals: Encode policies that kill entire classes of paths.
  • Instrument choke points: Focus monitoring where backward paths converge.
  • Pre-mortem drills: Assume breach, walk the graph, prove refusals hold.

🔍 Example: AWS S3 Bucket Data Exfiltration

Step 1 - Desired Outcome:

Attacker downloads sensitive customer data from S3 bucket.

Step 2 - Constraints & Affordances:

  • Affordance: Public read access if misconfigured
  • Constraint: IAM policies, bucket policies, encryption
  • Ambiguity: "Temporarily public" buckets for staging

Step 3 - Backward Pathways:

  • Direct: Compromised IAM credentials with s3:GetObject
  • Side channel: Public bucket URL left in GitHub repo
  • Pivot: Compromise EC2 with instance role → inherit S3 permissions

Step 4 - Choke Points:

  • IAM policy evaluation (all paths flow through this)
  • CloudTrail logging (silent success = no s3:GetObject logs)
  • Bucket versioning (counterfactual: delete without versions disappearing)

Step 5 - Defensive Inversion:

  • Motif: "Ambient Permissions" (overly broad IAM roles)
  • Refusal: Explicit deny for s3:* on sensitive buckets unless MFA
  • Instrument: Alert on any s3:GetObject from outside VPC
  • Pre-mortem: Assume role compromised → prove refusal holds

Core Questions to Keep in Mind

  • What is the end state I’m assuming?
  • What must be true for that end state to exist?
  • What are the affordances the system gives me?
  • What are the constraints that resist me?
  • What are the side channels or overlooked paths?
  • Where are the pivot nodes that magnify small wins?
  • What are the silent signals of success or failure?
  • If I invert this path, what policy or refusal kills it?
  • How do I prove inevitability or prove refusal?

🧾 Compact Template (Reusable)

Goal/Objective:
Invariants:
Affordances:
Constraints:
Backward Paths:
Choke Points:
Silent Signals:
Refusals:
Drill/Proof:

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