Eavesdropping: SSHv2 protects against eavesdropping by encrypting all data, making it unreadable to potential eavesdroppers.

Domain Name System (DNS) and IP spoofing: SSHv2 wards off such attacks by cryptographically verifying the identity of the server. For every session, the SSH client validates the server's host key against a local list of available keys that are associated with server names and addresses. If the keys do not match, an immediate warning is issued.

Session hijacking: SSHv2 is unable to prevent hijackings because of an inherent flaw in the TCP layer. SSHv2 can, however, render the hijacking ineffective through its integrity-checking process. If a session is modified during transmission, SSHv2 will shut down the connection immediately without using the bogus data. SSHv2 uses the cryptographically strong hash functions MD5 and SHA-1 for integrity checking. This can also prevent replay or insertion attacks.

Protection against man-in-the-middle, or replay attacks: The man-in-the-middle attack is one of the biggest threats on an Ethernet network today.