TL;DR: A program or method that exploits a vulnerability in software or a system to gain unauthorised access or control or to cause damage.
An exploit is a specific type of software, data fragment or sequence of commands that takes advantage of vulnerabilities or security holes in a computer system, application or network to gain unauthorised access or control. Exploits are often a key tool used by attackers to compromise systems and carry out malicious activities.
Types of exploits:
- Remote exploits: These exploits target vulnerabilities in a system via a network. An attacker can access and manipulate a target system without having physical access. Examples include exploits that attack web applications or network services.
- Local Exploits: These exploits require physical or existing access to a system. They are used to gain privileged rights or to exploit other vulnerabilities. One example is an exploit that uses a vulnerability in the operating system to gain administrator rights.
- Client-side exploits: These exploits target vulnerabilities in client applications, such as web browsers, email clients or media players. A common scenario is the sending of a manipulated link or file that triggers the exploit when the user clicks on it.
Examples of types of exploits:
- Buffer overflow: A common exploit in which an attacker writes more data to a buffer than it can hold. This can lead to the excess code being written to neighbouring memory areas and executed there, often with elevated privileges.
- SQL Injection: An exploit in which an attacker inserts malicious SQL code into a web form input to access or manipulate the database.
- Zero-day exploits: These exploits take advantage of unknown or unpatched vulnerabilities that have not yet been fixed by software developers. Zero-day exploits are particularly dangerous as no existing security measures or patches are effective against them.
Protective measures against exploits:
- Regular software updates: Installing security updates and patches to fix known vulnerabilities.
- Security software: Use of firewalls, intrusion detection/prevention systems (IDS/IPS) and anti-virus programmes.
- Safety awareness and training: Sensitising users to potential threats and training them in the safe handling of emails, links and attachments.
- Security configurations: Implementation of security configurations that restrict and monitor access to systems and applications.
An exploit poses a significant threat to the security of computer systems and networks. It is therefore crucial to take proactive security measures to identify and eliminate vulnerabilities before they can be exploited by attackers.