Race Condition Hackviser May 2026

race condition

The story of a (often encountered on platforms like Hackviser or TryHackMe ) is essentially a tale of two actions running toward the same finish line, where the winner isn't who you’d expect. The Scene: The Midnight Bank Transfer

Pessimistic Locking

: The OWASP community recommends "locking" Alex's account row the moment Request A starts, forcing Request B to wait in line until Request A is completely finished and the balance is zero. race condition hackviser

  1. Code Reviews: Regular code reviews were conducted to identify and address potential vulnerabilities.
  2. Thread-Safe Programming: Developers were trained on thread-safe programming practices, including the use of locks and semaphores.
  3. Penetration Testing: Regular penetration testing was performed to identify vulnerabilities and weaknesses in the system.
  4. Incident Response: An incident response plan was put in place to quickly respond to and contain security incidents.

Target:

Linux futex waiter list corruption (no published fix at time) race condition The story of a (often encountered

The exploit, cleverly disguised as a benign user request, was crafted to trigger the following sequence of events: Code Reviews : Regular code reviews were conducted

The Hackviser "Race Condition" lab demonstrates how to exploit timing vulnerabilities by sending multiple concurrent requests to bypass check-then-act logic, such as in coupon redemption or fund withdrawal. Exploitation often involves using Burp Suite to send parallel requests to maximize the race window between a system check and its state update, allowing for unauthorized actions. Remediation requires implementing atomic database operations or proper locking mechanisms to ensure secure concurrent processing.

—a tiny period between when a system checks a condition (e.g., "does this user have enough money?") and when it finalizes an action (e.g., "deduct funds and transfer"). Sub-states:

  1. The Attacker Loop: Continuously swaps a symlink between a "dummy" file (we own) and the "target" file.
  2. The Victim Loop: Continuously runs the SUID binary.