0.16.1 Asymmetric warfare – the attacker only needs to win once

2025.10.06.
AI Security Blog

Imagine defending a fortress with a thousand doors. You must keep every single one locked, all the time. The attacker only needs to find one that is unlocked, just for a moment. This is the fundamental asymmetry of security, and it defines the landscape of AI system defense.

In cybersecurity, this principle is a well-worn truth. For AI systems, the asymmetry is amplified. The “doors” are not just network ports and software vulnerabilities; they are the training data, the model architecture, the inference logic, and the very way the system perceives the world. This creates an expansive and complex attack surface that is far more difficult to secure completely.

Kapcsolati űrlap - EN

Do you have a question about AI Security? Reach out to us here:

The Defender’s Dilemma: The Burden of Perfection

As a defender of an AI system, your task is Sisyphean. You are responsible for securing the entire lifecycle of the model, from data ingestion to deployment and monitoring. A single lapse in any area can compromise the entire system. Your mandate is to be right 100% of the time.

Your responsibilities include:

  • Comprehensive Data Security: Protecting training data from poisoning, ensuring its integrity, and managing its provenance.
  • Robust Model Architecture: Designing models that are inherently more resistant to adversarial evasion, extraction, and inversion attacks.
  • Secure MLOps Pipeline: Hardening every component of the CI/CD pipeline, from code repositories to artifact storage and deployment triggers.
  • Hardened Inference Endpoints: Implementing strict input validation, rate limiting, and authentication/authorization for all API calls.
  • Continuous Monitoring: Actively monitoring for data drift, concept drift, and anomalous prediction patterns that could indicate an attack.
  • Proactive Patching: Staying ahead of vulnerabilities not just in your code, but in all the third-party libraries and frameworks your system depends on.

The cost of this constant vigilance—in terms of time, resources, and personnel—is immense. You are playing a game of infinite defense on a constantly shifting battlefield.

The Attacker’s Advantage: The Luxury of a Single Success

The attacker operates under no such constraints. They are not required to be perfect or comprehensive. They can afford to fail repeatedly, learning from each attempt. Their goal is singular: find one exploitable flaw. This focus gives them a significant strategic advantage.

Diagram illustrating the asymmetry between attacker and defender. Defender’s AI System (Many Defenses) Data Validation API Security Monitoring Model Hardening Input Flaw A Attacker Single Successful Exploit

Case Study: Bypassing a Content Moderation AI

Consider an AI model designed to filter harmful content. The defense team has implemented multiple layers of protection. An attacker, however, can probe methodically until a single weakness is found.

Defender’s Continuous Tasks Attacker’s Iterative Attempts
Monitor and defend against known hate speech keywords and phrases. Attempt 1: Use simple keyword variations. (Blocked)
Implement image hashing to block known harmful images. Attempt 2: Upload a slightly modified known image. (Blocked)
Train the model to understand context and nuance in text. Attempt 3: Use sarcasm or coded language. (Blocked)
Validate and sanitize all text inputs to prevent injection-style attacks. Attempt 4: Use a zero-width space character inside a forbidden word to break the filter’s string matching. (SUCCESS)

In this scenario, the defense team succeeded three times, but the attacker only needed to succeed once. That single successful bypass invalidates much of the defensive effort until it is discovered and patched, during which time significant harm can occur.

The Attacker’s Code Logic

An attacker’s approach can be modeled as a simple loop: try, fail, learn, and repeat. They can automate this process to probe thousands of potential vulnerabilities with minimal effort.

# Pseudocode representing an attacker's automated probing script
payloads = [
    generate_evasion_text("variant_1"),
    generate_evasion_text("leetspeak"),
    generate_evasion_text("homoglyphs"),
    generate_evasion_text("zero_width_joiner"), # The payload that might succeed
    generate_prompt_injection("role_play_attack"),
    ... # Potentially thousands more
]

for payload in payloads:
    print(f"[*] Testing payload: {payload[:30]}...")
    response = target_moderation_api.submit(payload)

    if response.status == "approved":
        print(f"[+] SUCCESS! Payload bypassed the filter: {payload}")
        # The attacker has won. They can now stop and exploit this vulnerability.
        break
    else:
        print(f"[-] FAILED. Model correctly blocked the payload.")

Implications for AI Red Teaming

This fundamental asymmetry is precisely why AI red teaming is not just valuable, but essential. Your role as a red teamer is to embrace the attacker’s advantage for the benefit of the defender.

You are not expected to validate every defense. Your mission is to find a single, impactful failure. By thinking and acting like the adversary—patiently, creatively, and with a focus on a single success—you uncover the “unlocked doors” that automated scanners and defensive checklist approaches miss. Each vulnerability you find is one less opportunity for a real attacker. You are, in effect, weaponizing the defense paradox against itself to build more resilient systems.