A web skimmer, also known as a Magecart skimmer, is a type of malicious software or code used by cybercriminals to steal sensitive information from online payment forms or checkout pages on compromised websites.
Web skimmers are typically injected into legitimate websites by exploiting vulnerabilities or compromising third-party scripts used on the site. Once injected, the skimmer collects payment card details, including credit card numbers, names, addresses, and CVV codes, entered by unsuspecting users during the checkout process.
Web skimmers work by intercepting and capturing user input in real-time. When a user enters their payment information into a compromised web form, the skimmer captures the data and sends it to a server controlled by the attackers. The stolen data can then be used for fraudulent transactions, sold on underground marketplaces, or utilized for identity theft purposes.
Web skimmers are often difficult to detect because they operate silently in the background, blending in with the legitimate code of the compromised website. Users may not realize that their information is being skimmed until unauthorized transactions occur or they become victims of fraud.