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CRLF injection

CRLF injection definition

CRLF Injection is a cyber attack where hackers insert malicious characters into web application input fields to cause unexpected behavior. This is commonly done by modifying an HTTP parameter or URL.

The term “CRLF“ stands for Carriage Return (CR) and Line Feed (LF). These are the special characters used for formatting text in some computer systems.

See also: Code injection

The history of CRLF injection

In the late 1990s and early 2000s, some cunning cyber attackers stumbled upon a clever trick. They found that by sneaking special characters like Carriage Return (CR) and Line Feed (LF) into input fields, they could cause unexpected mayhem. These characters were used to format text in certain computer systems.

When web applications processed the input containing these sneaky characters, it caused all sorts of mischief. The attackers could manipulate the application in unexpected and potentially harmful ways, wreaking havoc and causing headaches for everyone involved.

As the word got out about this crafty attack, security experts and developers stepped up their game. They worked tirelessly to safeguard web applications from CRLF Injection. They devised smart methods to carefully validate and sanitize input data, ensuring that the malicious characters wouldn't cause any harm.

Even today, CRLF Injection remains a worrisome cybersecurity challenge. Website owners and developers continue to team up and stay vigilant.