Patched code sample

Since CVE-2025-67485 is a fictional vulnerability identifier and does not correspond to a real issue in a real library, an actual fix cannot be provided.

However, based on the description of "bypassing HTTP/HTTPS traffic interception rules," a plausible hypothetical vulnerability would involve improper or incomplete validation of the request's host or path. A common bypass technique involves case-insensitivity, where a rule blocks `example.com` but not `Example.com`.

The following Python code demonstrates a hypothetical vulnerable function and its corresponding fixed version, which addresses such a bypass.

```python
# This code is a hypothetical example to demonstrate a potential fix for a
# vulnerability as described. It is not a fix for a real CVE.

import re

# A hypothetical set of rules to block traffic to certain domains.
BLOCKED_DOMAINS = {"sensitive-data.com", "malicious-site.net"}

# A more robust, pre-compiled set for the fixed version.
# We store everything in lowercase for case-insensitive matching.
BLOCKED_DOMAINS_LOWER = {domain.lower() for domain in BLOCKED_DOMAINS}

# Pre-compile regex for efficiency in the fixed version.
# This pattern will match any subdomain of the blocked domains.
BLOCKED_PATTERN = re.compile(
    "|".join(re.escape(domain) for domain in BLOCKED_DOMAINS_LOWER) + "$",
    re.IGNORECASE
)


class HypotheticalRequest:
    """A simple class to simulate an incoming HTTP request."""
    def __init__(self, host_header):
        self.host = host_header

# --------------------------------------------------------------------------
# VULNERABLE IMPLEMENTATION (Represents versions 0.3 and below)
# --------------------------------------------------------------------------
# This version is vulnerable because it performs a simple, case-sensitive
# check, allowing trivial bypasses.

def is_blocked_vulnerable(request: HypotheticalRequest) -> bool:
    """
    Vulnerable check: only blocks if the host header matches exactly
    (case-sensitive) one of the entries in the blocklist.
    """
    # Flaw: A simple `in` check is case-sensitive.
    # An attacker can use "Malicious-Site.net" to bypass the rule
    # for "malicious-site.net".
    if request.host in BLOCKED_DOMAINS:
        return True
    return False


# --------------------------------------------------------------------------
# FIXED IMPLEMENTATION (Represents a patched version)
# --------------------------------------------------------------------------
# This version fixes the bypass by normalizing the host header to lowercase
# before checking it against a normalized blocklist. It also uses a more
# robust regex match to handle subdomains correctly.

def is_blocked_fixed(request: HypotheticalRequest) -> bool:
    """
    Fixed check: normalizes the host to lowercase and uses a case-insensitive
    regex to check if it ends with a blocked domain.
    """
    if not request.host:
        return False

    # Fix 1: Normalize the input to lowercase to prevent case-sensitivity bypasses.
    host_lower = request.host.lower()

    # Fix 2: Use a robust pattern match instead of a simple `in`.
    # This correctly blocks "sub.malicious-site.net" as well as
    # "Malicious-Site.net".
    if BLOCKED_PATTERN.search(host_lower):
        return True

    return False


# --- Demonstration ---
if __name__ == '__main__':
    # This part is for demonstration and would not be part of the library code.
    
    test_cases = [
        HypotheticalRequest("google.com"),             # Should be allowed
        HypotheticalRequest("sensitive-data.com"),      # Should be blocked
        HypotheticalRequest("Sensitive-Data.com"),      # Bypass attempt
        HypotheticalRequest("malicious-site.net"),      # Should be blocked
        HypotheticalRequest("api.malicious-site.net"),  # Subdomain bypass attempt
        HypotheticalRequest("MALICIOUS-SITE.NET"),      # Case bypass attempt
        HypotheticalRequest("not-malicious-site.org"),  # Should be allowed
    ]

    print("--- Demonstrating Vulnerable vs. Fixed Logic ---")
    print(f"{'Host':<30} | {'Vulnerable (Allowed?)':<25} | {'Fixed (Allowed?)'}")
    print("-" * 75)

    for req in test_cases:
        vulnerable_allowed = not is_blocked_vulnerable(req)
        fixed_allowed = not is_blocked_fixed(req)
        
        # Highlight bypasses
        vuln_status = f"{vulnerable_allowed}"
        if vulnerable_allowed and not fixed_allowed:
            vuln_status += " (BYPASS!)"
            
        print(f"{req.host:<30} | {vuln_status:<25} | {fixed_allowed}")