The U.S. Department of Homeland Security Cybersecurity and Infrastructure Security Agency (CISA) advises it is aware of open-source reporting of targeted denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks against finance and business organizations worldwide. A DoS attack is accomplished by flooding the targeted host or network with traffic until the target cannot respond or simply crashes, preventing access for legitimate users. In a DDoS attack, the incoming traffic originates from many different sources, making it impossible to stop the attack by blocking a single source. These attacks can cost an organization both time and money while their resources and services are inaccessible. CISA adds that if you think you or your business is experiencing a DoS or DDoS attack, it is important to contact the appropriate technical professionals for assistance. It offers some additional considerations to assist and refers to its Understanding Denial-of-Service Attacks tip. Read the advisory at CISA.