Sniffers are programs that record and often analyze the data traffic of a network. Their name is derived from the English word “sniff”.
Sniffers were originally developed for legitimate purposes: to monitor, analyze and optimize networks. They are still used in this function today.
But cyber criminals also use sniffers. They can use them to record the data traffic of a network and thus obtain sensitive information. For example, passwords, login data, bank details or credit card information. Sniffers spy on an entire network – and therefore all data traffic between all computers connected to this network.
A sniffer does not have to be installed on your computer in order to spy on your data traffic. It is sufficient for it to be active in your network. For this reason, hackers like to place sniffers in public Wi-Fi networks, e.g. in cafés, hotels and airports. All unencrypted data that you send or receive in this network can then be read by the sniffer. Like other malware, sniffers can be installed on your computer without your consent. This installation can take place via Trojans, viruses or worms, for example via infected email attachments. If cyber criminals can gain access to your network or computer via a backdoor, for example, they can also install a sniffer manually.
You will certainly come across sniffers frequently in legitimate use. Many administrators use them to monitor networks and analyze data traffic. Legitimate sniffers are also used to detect criminal sniffers. You can potentially encounter sniffers used by cyber criminals on many occasions. For example, with every email attachment and in every public WLAN.
