CVE-1999-1218

Step 1: Local Access: The attacker must have local access to the vulnerable system, either through physical access, an existing compromised account, or another vulnerability.

Step 2: Crafting the Input: The attacker crafts a malicious input string to be passed to the finger utility. This input includes the path to the target file they want to read.

Step 3: Invoking Finger: The attacker executes the finger command with the crafted input, specifying the target file path.

Step 4: File Reading: The finger utility, due to the lack of input validation, reads the contents of the specified file.

Step 5: Information Disclosure: The contents of the target file are displayed to the attacker, revealing sensitive information.

The vulnerability stems from a flaw in the finger utility's handling of user-supplied input, specifically related to how it processes file paths. The finger utility, when invoked with a crafted input, fails to properly validate the input, allowing an attacker to specify an arbitrary file path. This leads to the utility reading and displaying the contents of the specified file. The root cause is a lack of input validation and sanitization, allowing the attacker to bypass security checks and access restricted files. This is not a buffer overflow or race condition, but a simple path traversal vulnerability.