Exploit kits are a form of 'crimeware' - a specialized utility program that is created and sold to facilitate illegal computer-related activity.
Each exploit kit has a library or collection of exploits that it can use to target vulnerabilities in different types of computers, devices, programs and so on. They are also usually designed so that their library can be updated easily whenever new exploits are released for recently discovered vulnerabilities. This makes it easy for the kit's operators to keep up-to-date and effective.
Probing for and exploiting vulnerabilities
Exploit kits are often planted by attackers on a webpage, where they can silently probe the computer or device of any visitor that views the page. The webpage may either be deliberately created by an attacker to contain the exploit kit, or it may be a legitimate page that was compromised by an attacker who then injected the kit onto it.
When a user views the webpage, the exploit kit silently probes their computer or device to see if it has any vulnerabilities that the kit can target with one of the exploits in its library. If one is found, the kit will launch the appropriate exploit for it.
If the exploit successfully compromises the user's computer or device, the exploit kit then proceeds with its actual payload, which may range from installing components on the affected system, stealing data and so on.
Examples of exploit kits include AnglerEK, Fiesta, Styx, SweetOrange, Archie and Astrum. For more information on these kits:
For more about exploit kits, see Article: Exploit Kits