Sniffing is a way to trace, intercept, and read data as it is being transmitted over public networks like the internet. It is used by developers and security experts to identify issues and optimize data transfer and by criminals and other bad actors to steal data and gain unauthorized access to computer systems.

Terms related to Sniffing: Cybersecurity, Networks, Encryption, Hackers, Penetration Testing, Vulnerability Scanning, TLS, SSL.

Data is typically transmitted across networks using “packets” — these are discrete pieces of data that are created, transmitted, received, analyzed, and acted on by various technologies, hardware, and software. Every time a user browses a website, uses an internet service, sends an email, or otherwise interacts using an application on a public network or the internet, the technology they use is creating and receiving these data packets.

Data packets can be traced, intercepted, and analyzed using specialized data and packet sniffing software. Legitimate users like developers, network engineers, and security personnel use packet sniffers to optimize the creation, sending, transfer, and receiving of data. Packet sniffers can also help to identify vulnerabilities in computer networks and work alongside penetration testing and vulnerability identification that allows cybersecurity engineers to close the gaps in their network security.

Criminals and other bad actors use packet sniffers to trace and steal data transmitted across an open, public network. This is a significant issue if usernames and passwords are being transferred in an unencrypted way, as the criminal can then imitate an authorized user to gain access.

Cybersecurity teams can defend against criminals through securely-encrypting data before it’s transmitted using protocols like TLS or SSL. This adds a secure layer of encryption to data transmissions, making it very difficult to decrypt data, even if it is intercepted by a packet sniffer. Multifactor authentication adds an additional level of security that makes it more difficult for an attacker to gain unauthorized access.