USTB Contract Security Audit

Audit Report Revisions

Audit Overview

We were tasked with performing an audit of the Tangible codebase and in particular their USTB token module meant to represent a cross-chain LayerZero rebasing token implementation.

Over the course of the audit, we identified a significant flaw in relation to the USTB token and its burning operation that would render all USTB balances held prone to compromisation as the burn operation was insecure.

We advise the Tangible team to closely evaluate all minor-and-above findings identified in the report and promptly remediate them as well as consider all optimizational exhibits identified in the report.

Post-Audit Conclusion

The Tangible team iterated through all findings within the report and provided us with a revised commit hash to evaluate all exhibits on.

We evaluated all alleviations performed by Tangible and have identified that all exhibits have been adequately dealt with no outstanding issues remaining in the report.

Post-Audit Conclusion (d2f37f8580)

The Tangible team expanded the test suites of their USTB token in the latest commit and performed non-functional changes to the USTB contract including a relocation of its event declarations as well as documentation to its interface.

The code is functionally identical to the original with the sole differentiator being a newly introduced publicly available view function that simply exposes an internal one.

As such, we consider the original security guarantees of the audit upheld in the latest commit and it being covered under this audit engagement.

Audit Synopsis

Severity	Identified	Alleviated	Partially Alleviated	Acknowledged
	0	0	0	0
	1	1	0	0
	0	0	0	0
	0	0	0	0
	1	1	0	0

During the audit, we filtered and validated a total of 0 findings utilizing static analysis tools as well as identified a total of 2 findings during the manual review of the codebase. We strongly recommend that any minor severity or higher findings are dealt with promptly prior to the project's launch as they can introduce potential misbehaviours of the system as well as exploits.

Total Alleviations

The list below covers each segment of the audit in depth and links to the respective chapter of the report:

• 🎯 Scope
• 💻 Compilation
• 🔍 Static Analysis
• 👁️ Manual Review
• 🖋️ Code Style