Catastrophic backtracking: how can a regular expression cause a ReDoS vulnerability?

Regular expressions come in handy when you need to search for and replace text. However, in some cases, they may cause the system to slow down or even make vulnerable to ReDoS attacks.

Introduction

ReDoS is a subtype of a DoS attack. The aim of a ReDoS attack is to halt an application or cause it to slow down via an inefficient regex.

ReDoS attacks can be divided into two types:

1. A string with a malicious pattern is passed …

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