22.2 Vault security audit and property tests

[determined-001]

Labels: type:security type:test area:contracts priority:critical
Milestone: Phase 4 - Workers W4: latency-sensitive and vault
Effort: High
Depends on: 22.1

Description

The vault holds user funds. Unit tests prove the cases someone thought of;
property tests and an external audit are how the cases nobody thought of get
found before a user does.

No W4 automation ships against an unaudited vault.

Acceptance criteria

• Property tests assert the invariants: funds only ever return to their
  depositor; the allow-list only narrows; slippage bounds always hold; worker
  authority never widens
• Fuzzing over deposit/withdraw/action sequences, including interleaved and
  reentrant orderings
• External audit commissioned and the report published in the repo
• Every audit finding is either fixed or has a written accepted-risk rationale
• Audit report and its commit are linked from SECURITY.md
• Deployment to mainnet is gated on audit completion, stated in the runbook

Implementation notes

1. State the invariants as properties first, then fuzz against them - a fuzzer
   with no invariant is a slow random test.
2. Publishing the report, including accepted risks, is worth more to the
   regulated-money audience than a clean-looking summary.
3. Audit scheduling is maintainer work with lead time; start it while 22.3-22.5
   are in progress rather than after.

Affected files

• contracts/vault/tests/property.rs
• contracts/vault/tests/fuzz.rs
• docs/audits/
• SECURITY.md

[Vanessa388]

@Vanessa388 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, I would love to work on this issue. Thanks

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[Kingsilva36]

@Kingsilva36 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would love to work on this professionally, please assign it to me

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[devprom6]

@devprom6 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I’d like to work on this issue because it addresses an important area of the project and presents a great opportunity to make a meaningful contribution. I’m particularly interested in delivering a solution that is reliable, maintainable, and aligned with the project’s existing architecture and development standards.

I have experience working across software development, including backend and frontend development, APIs, databases, testing, DevOps, and blockchain-based applications. I’m comfortable understanding existing codebases, identifying the root cause of issues, implementing clean and scalable solutions, and writing thorough tests to prevent regressions.

My approach would be to first understand the existing implementation and project conventions, then develop the solution in a focused and incremental way. I’ll ensure the changes are well-tested, documented where necessary, and do not introduce unnecessary complexity or break existing functionality. I’m also committed to clear communication, responding to review feedback, and delivering a polished contribution that provides real value to the project.

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[Gentleslyl2006]

@Gentleslyl2006 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello maintainer.
I have read the description of this ISSUE and with with confidence I assure you best of results if you assign this issue to me

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[Adeoye7]

@Adeoye7 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, maintainer,I will be very pleased to work and solve this issue,kindly assign me the issue, thank you in advance

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[ibochivincent-lang]

@ibochivincent-lang has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I’d like to work on Issue #1069 because the vault holds user funds, so ordinary unit tests alone are not enough to provide confidence that unexpected interaction sequences cannot break the security model. Property testing, fuzzing, and an external audit are important before any W4 automation relies on the vault.

I will first review the vault implementation from #22.1 and identify the core security properties that must always remain true. I will write these invariants down before building the fuzz tests so the generated scenarios are checked against meaningful guarantees rather than simply producing random transactions.

The property tests will cover the required invariants: funds can only be withdrawn to the original depositor, the allow-list can only become more restrictive, configured slippage limits cannot be bypassed, and worker authority cannot expand beyond what the vault configuration permits.

I will then add sequence-based fuzzing around deposits, withdrawals, and vault actions, including different transaction orderings and reentrant-style interaction cases supported by the contract architecture. The tests will focus on state transitions and verify that the security properties continue to hold after long or unusual sequences.

For the external audit, I will prepare the vault for independent review and document the resulting report under docs/audits/. Each finding will be tracked to either a code fix or a clearly written accepted-risk rationale so there is an auditable record of how every issue was handled.

I will update SECURITY.md with a direct link to the audit report and the corresponding commit, making the review easy for users and maintainers to verify.

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