Finger Protocol - Security Concerns

Security Concerns

Supplying such detailed information as e-mail addresses and full names was considered acceptable and convenient in the early days of networking, but later was considered questionable for privacy and security reasons. Finger information has been frequently used by hackers as a way to initiate a social engineering attack on a company's computer security system. By using a finger client to get a list of a company's employee names, email addresses, phone numbers, and so on, a cracker can telephone or email someone at a company requesting information while posing as another employee. The finger daemon has also had several exploitable security holes which crackers have used to break into systems. The Morris worm, in 1988, exploited an overflow vulnerability in fingerd (among others) to spread. The finger protocol is also incompatible with Network Address Translation (NAT) from the private network address ranges (e.g. 192.168.0.0/16) that are used by the majority of home and office workstations that connect to the Internet through routers or firewalls.

For these reasons, while finger was widely used during the early days of Internet, by the late 1990s the vast majority of sites on the internet no longer offered the service.