On a standard Linux system:
import os
def secure_file_access(requested_path, base_directory):
# Normalize the path
full_path = os.path.normpath(os.path.join(base_directory, requested_path))
# Check if the full path starts with our base directory
if not full_path.startswith(base_directory):
raise ValueError("Path traversal attempt detected")
# Proceed with file operations
if os.path.exists(full_path):
# File exists, proceed with reading or serving the file
pass
else:
# Handle the case when the file does not exist
pass
# Example usage:
base_dir = "/var/www/"
requested_path = "../../../root/etc/passwd"
try:
secure_file_access(requested_path, base_dir)
except ValueError as e:
print(e)
If this payload is successful, the consequences can be severe: -include-..-2F..-2F..-2F..-2Froot-2F
URL encoding is a mechanism for encoding information in a Uniform Resource Identifier (URI) using only the limited US-ASCII characters. It's often used to avoid special character conflicts in URL paths and query strings. The %2F in the path is an example of URL encoding for the / character. On a standard Linux system: