safe_finger

safe_finger [options] [user]

user
    The username to query information for. If omitted, information about all logged-in local users might be displayed, depending on the specific implementation of safe_finger.

options
    Specific options are highly dependent on the particular safe_finger implementation. Common finger-like options such as -s (short format) or -m (exact match) might be supported, but extensive options are unlikely given its security-focused nature. Typically, it defaults to the most secure and restricted output.

The safe_finger command is typically a wrapper or a custom implementation designed to provide a more secure and restricted version of the traditional finger command. The standard finger command is often disabled on modern systems due to security concerns, as it can reveal sensitive user information such as login times, idle times, and .plan or .project files, potentially aiding attackers in reconnaissance. safe_finger aims to mitigate these risks by enforcing stricter access controls or limiting the amount of information disclosed. It might only allow querying local users, restrict output to basic user details (e.g., username, full name, terminal), or require specific permissions to execute. Its primary purpose is to allow system administrators to retain some user information lookup capability without exposing excessive data. It's not a standard Linux utility and is usually found in hardened environments or custom setups where controlled user information access is necessary.

The safe_finger command is not a standard Linux utility and its exact behavior, options, and output are entirely dependent on the specific implementation or wrapper script provided by a system administrator or distribution. It is typically designed to be a local-only tool or to restrict information disclosure significantly compared to the traditional finger command. Therefore, its capabilities and limitations will vary greatly. Relying on safe_finger for comprehensive user information is not advisable, as its primary goal is information restriction.

The concept of safe_finger emerged as a direct response to the inherent security vulnerabilities of the original finger command and protocol. The finger service, introduced in the early days of ARPANET and common on Unix-like systems, was designed for convenient user information lookup. However, its broad disclosure of details like login times, idle status, home directories, and user-editable .plan and .project files became a significant information leakage risk as internet security concerns grew. Many organizations disabled finger entirely. safe_finger, therefore, isn't a single, standardized command but rather represents a class of custom wrappers or restricted implementations developed by system administrators to regain some controlled user information lookup capability while minimizing the attack surface presented by the traditional finger utility. Its development is decentralized, driven by specific security requirements.

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