taint-instrumentation-assistant

Taint Instrumentation Assistant

Instrument code to track untrusted and sensitive data flow for security vulnerability detection.

Workflow

Follow these steps to add taint tracking instrumentation:

1. Identify Taint Sources and Sinks

Define what data to track and where violations occur:

Taint sources (untrusted/sensitive data origins):

• User input (HTTP parameters, form data, command-line args)
• File reads (configuration files, user uploads)
• Database queries (user-provided data)
• Network input (API responses, socket data)
• Environment variables

Taint sinks (dangerous operations):

• SQL queries (SQL injection risk)
• System commands (command injection risk)
• HTML output (XSS risk)
• File operations (path traversal risk)
• Eval/exec statements (code injection risk)
• Network output (data leak risk)

2. Instrument Taint Sources

Mark data from untrusted sources as tainted:

# Mark user input as tainted
def mark_tainted(value, source):
    """Mark a value as tainted from a specific source"""
    if hasattr(value, '__taint__'):
        value.__taint__ = source
    return value

# Example: HTTP parameter
user_input = request.GET['username']
user_input = mark_tainted(user_input, source="HTTP_PARAM")

3. Propagate Taint Through Operations

Track taint as data flows through the program:

# Taint propagation for string operations
def tainted_concat(str1, str2):
    result = str1 + str2
    # If either input is tainted, result is tainted
    if hasattr(str1, '__taint__') or hasattr(str2, '__taint__'):
        result.__taint__ = getattr(str1, '__taint__', None) or getattr(str2, '__taint__', None)
    return result

4. Check Taint at Sinks

Detect when tainted data reaches dangerous operations:

# Check for tainted data at SQL sink
def execute_query(query):
    if hasattr(query, '__taint__'):
        print(f"TAINT VIOLATION: Tainted data from {query.__taint__} used in SQL query")
        print(f"Query: {query}")
        # Optionally: raise exception or log for analysis
    # Execute query...