how to book ccna exam

how to book ccna exam.12.5 DNS Tunneling and Other "Data Entrainment" MethodsThis is an example of how DNS tunnels can be used.Threat makers have been using a variety of non-traditional techniques to steal data from within corporate networks without being detected. (11 For example, these individuals would use tunneling techniques to send stolen credit card data, intellectual property, and confidential files through DNS traffic. As readers will know, DNS is a protocol used to resolve domain names into IP addresses. The DNS protocoltraffic does not lend itself to being delivered using a command channel or even in a way that creates a tunnel. However, certain attackers have developed a variety of software for building DNS tunnels. Such threat makers often use protocols that are not normally used to transmit data to "smuggle data" because traffic from such protocols can often escape detection by security monitoring. DNS tunnels that are not detected by security monitoring (also known as DNS "data entrapment") are a significant risk for any organization.In many cases, malware uses Base64 encoding to place sensitive data (e.g., credit card numbers and PIIetc.) into the net load of a DNS packet and send it to a malicious party. The encoding methods that attackers may use are shown below. Base64 encoding method. Binary (8-bit) encoding.NetBIOS encoding method.Hexadecimal (Hex) encoding. Today, there are several utilities (both good and bad) that can be used to create DNS tunnels, as shown below.DeNiSe: A Python I tool that "tunnels" (entraps) TCP traffic through DNS packets.dns2tcp: written in C by Olivier Dembour and Nicolas Collignon, dns2tcp supports KEY and TXT request types.