safe_finger

safe_finger [options] [user ...]

-l
    Produces a long format, displaying more detailed information.

-p
    Suppresses the display of the user's .plan file.

-s
    Produces a short format, displaying less information.

user
    Specifies the user account to retrieve information about. Multiple users can be specified.

safe_finger is a security-conscious replacement for the standard finger command.
While finger can leak sensitive user information to the network, potentially aiding attackers, safe_finger aims to limit the information disclosed to only what is necessary and appropriate.

It is particularly focused on preventing the disclosure of .plan files, which can contain private details.
The command retrieves and displays information about users, typically including login name, full name, terminal name, idle time, login time, and potentially other details.
However, safe_finger is designed to be more restrictive about the data it presents, aiming to balance user information sharing with security concerns. It prioritizes local user information while being cautious about network-based queries. It is often configured to block remote requests.

The effectiveness of safe_finger depends on its configuration and how it's deployed within a system. If the underlying system allows access to sensitive information, safe_finger can only mitigate, not eliminate, the risk. Also, if the configuration is not restrictive enough, it can still leak information. This command is rarely used in modern systems, as more robust security measures are typically implemented.

The primary goal of safe_finger is to enhance security by limiting the amount of user information exposed. System administrators should carefully consider the configuration of safe_finger to ensure that it effectively protects sensitive data while still providing necessary user information.

safe_finger was developed as a response to the security vulnerabilities associated with the original finger command. In older systems, finger was commonly used to retrieve user information. However, it was recognized that this information could be exploited by attackers to gain insights into the system's user base and potential vulnerabilities. Therefore, safe_finger was created with the intention of restricting information leakage and mitigating the security risks associated with the standard finger command.

finger(1), w(1), who(1)