Hackviser organizes its training content into several key sections:

Progress to the Warm-ups section, which offers scenarios that get progressively harder. Detailed solution documents are available for every task to support the learning process.

Use a tool to send a "packet of death"—a group of requests designed to arrive at the server at the exact same moment.

def send(): for _ in range(10): requests.post(url, data=data)

: Modern testers leverage HTTP/2 protocol features to send multiple request frames concurrently inside a single TCP packet. This ensures the server receives and processes them at the exact same physical moment, eliminating network latency variables.

Advanced hackvisers manipulate TCP packets. Instead of sending the entire HTTP request, they send the last byte milliseconds late. This ensures that the server's threads all start processing the first 99% of the request simultaneously, but wait for the final byte. When it arrives, they all fire together.

This article will take you deep into the world of race conditions, exploring what they are, how they can be exploited, and how Hackviser’s practical training can help ethical hackers and developers turn this subtle bug into a powerful tool for defense.

Race Conditions Vulnerabilities I | by Ehxb | InfoSec Write-ups

—the tiny fraction of a second between a security check and the final action. A classic example is the Time-of-Check to Time-of-Use (TOCTOU) flaw. Imagine an application processing a discount code: The server verifies the code hasn't been used yet. The server applies the discount and marks the code as used.

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