Definition
A buffer overflow occurs when a program attempts to write more data to a fixed sized memory buffer than it can hold. This excess data spills over into adjacent memory locations, potentially overwriting critical program instructions or data. In practice, this vulnerability can be exploited by attackers to inject malicious code or disrupt normal program execution. Understanding buffer overflows is crucial for developers and security professionals to prevent system compromise and maintain data integrity. For instance, a web server receiving an overly long input string could suffer a buffer overflow, allowing an attacker to execute arbitrary commands. This differs from a denial of service attack, which aims to make a system unavailable, though a buffer overflow can certainly lead to denial of service. Knowledge of buffer overflows is fundamental for cybersecurity certifications like CompTIA Security+ and CySA+.