Problem

Given a Python function that processes a username, password, file path, and shell command, identify the security vulnerabilities and rewrite the function securely. Return a dictionary containing the detected issues and a corrected implementation that avoids command injection, path traversal, weak credential handling, and unsafe string construction.

Examples

Example 1:

Input: code snippet uses os.system("cat " + path), compares plaintext password directly, and opens user-controlled paths
Output: issues include command injection, insecure authentication check, and path traversal risk
Explanation: concatenating untrusted input into shell commands and file paths is unsafe.

Example 2:

Input: code snippet builds a command with user input but validates against an allowlist and uses safe path normalization
Output: fewer issues; rewritten code still replaces shell execution with safe library calls
Explanation: validation helps, but avoiding shell execution entirely is stronger.

Constraints

• Input code length is between 1 and 10^5 characters
• The solution should detect multiple vulnerability patterns in one pass where practical
• The rewritten code must be valid Python and avoid shell-based execution for file reads
• Use deterministic pattern checks; no external security scanners