Path Traversal via User-Controlled File Path

Description

User input passed to open() may allow path traversal attacks. This can expose or overwrite arbitrary files on the server. Validate file paths and ensure they remain within a trusted directory.

Examples

Insecure Code

open(user_input, 'r')

Secure Code

import os
def safe_open_file(filename, base_path):
    abs_path = os.path.abspath(filename)
    if not abs_path.startswith(base_path):
        raise ValueError("Invalid path")
    return open(abs_path, 'r')

Remediation

Validate file paths using a trusted directory and ensure they do not allow traversal outside of it.

Rule Details

Field	Value
ID	CODE-0252
Category	Injection
Severity	CRITICAL
CWE	CWE-22
Confidence	HIGH
Impact	HIGH
Likelihood	MEDIUM
Exploitability	EASY
Tags	path traversal, file inclusion
OWASP	A01:2021-Broken Access Control

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