Intro
In the world of DeFi and automated trading, precision is everything. A single rounding error or a missing truncation logic can lead to a "death by a thousand cuts" where users lose small fractions of their funds over thousands of transactions. Today, I decided to perform a quick "Black-box" audit on a popular trading protocol's web application to see how they handle their math under the hood.
The Method: No Source Code? No Problem.
When the source code is private, a security researcher’s best friend is the Browser DevTools (Network Tab). By intercepting the communication between the Frontend and the Backend/Smart-contracts, we can see the "raw" data before it gets prettified for the user.
The Findings: The "8-Decimal" Red Flag
While analyzing the trade history of a strategy, I noticed a significant inconsistency in the API responses.
- UI Inconsistency In the user interface, profit values were displayed with an unusual number of decimal places (e.g., 4.18489805 USDT). For a stablecoin display, this is more than just a UI bug; it’s a sign that the data isn't being normalized.
- Deep Dive into the JSON Response Looking at the deals endpoint, the raw JSON confirmed my suspicions.
The profit field returned a string with 8 decimals: "4.18489805".
In the same object, total_profit was truncated to 2 decimals: "7.94".
Why This Matters (The Security Risk)
This inconsistency suggests that the protocol's architecture lacks a unified Math/Precision library.
Rounding Direction: If one part of the system rounds up and another rounds down (or doesn't round at all), it creates arbitrage opportunities or "ghost" funds.
Truncation Issues: If the backend isn't truncating these "long-tail" decimals, it might be performing internal calculations with floating-point math instead of fixed-point integer math (which is a cardinal sin in blockchain security).
Conclusion
Even without looking at the Solidity code, we can see that the data handling layer has gaps. For developers, the lesson is simple: Always normalize your precision at the API level and ensure your rounding directions are consistent across all modules.
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