| name | ai-llm-dos |
| description | Unbounded-consumption / denial-of-wallet attacks on LLM apps — force runaway tokens, cost, or latency. Load when testing an LLM product's limits/billing, on "LLM DoS", cost amplification, or resource exhaustion. Signals: user-controlled prompts/max_tokens, agent loops, no rate/'cost caps'.
|
| domain | ai-ml |
| type | technique |
| stability | learning |
| modes | ["bugbounty","defense"] |
| severity | medium |
| owasp_llm | ["LLM10:2025-Unbounded-Consumption"] |
| cwe | ["CWE-770","CWE-400"] |
| tools | [] |
| schema_version | 1 |
LLM unbounded consumption (denial-of-wallet)
When it applies
An LLM feature lets users drive expensive computation with weak limits. Unlike classic DoS, the
damage is often financial (the provider bills per token) — "denial of wallet" — plus latency/availability.
Why it works
Inference cost scales with tokens and calls. If the app lets users control input size, output
length (max_tokens), recursion (agent loops, tool chains), or call volume without hard caps, an
attacker amplifies cost/latency far beyond normal use.
Method
- Input amplification: send very long inputs, or inputs that induce very long outputs
("repeat X 10000 times", "write an exhaustive…"); push
max_tokens if client-controlled.
- Recursion / loops: with agents, craft prompts that trigger long tool-call loops or
self-referential expansion (→
ai-agent-tool-abuse) that burn calls.
- Volume: bypass rate limits (→
web-rate-limit-bypass) and fan out concurrent expensive requests.
- Retrieval blow-up: in RAG, queries that pull huge context each call multiply token cost.
- Measure impact: latency spike, error/timeout rates, or (where visible) token/cost per request × achievable rate.
Gotchas
- Frame it as impact (cost/availability), not just "it was slow" — quantify tokens/cost or a service degradation.
- Respect RoE strictly — this can run up real bills / affect availability; prove with minimal, controlled requests, don't sustain an outage.
- Defenders: cap input/output tokens, per-user quotas & spend caps, loop/tool budgets, timeouts.
Verify success
A single request (or a modest, controlled burst) demonstrably drives disproportionate token/cost or
latency — showing missing consumption limits.
References
OWASP LLM Top 10 (2025) LLM10; "denial of wallet" research; provider rate/quota docs.
