PraisonAI: Coarse-Grained Tool Approval Cache Bypasses Per-Invocation Consent for Shell Commands

## Summary The approval system in PraisonAI Agents caches tool approval decisions by tool name only, not by invocation arguments. Once a user approves `execute_command` for any command (e.g., `ls -la`), all subsequent `execute_command` calls in that execution context bypass the approval prompt entirely. Combined with `os.environ.copy()` passing all process environment variables to subprocesses, this allows an LLM agent (potentially via prompt injection) to silently exfiltrate API keys and credentials without further user consent. ## Details The `require_approval` decorator in `src/praisonai-agents/praisonaiagents/approval/__init__.py:176-178` checks approval status by tool name only: ```python @wraps(func) def wrapper(*args, **kwargs): if is_already_approved(tool_name): # line 177 — checks only tool_name return func(*args, **kwargs) # line 178 — bypasses ALL approval ``` The `mark_approved` function in `registry.py:144-147` stores only the tool name string: ```python def mark_approved(self, tool_name: str) -> None: approved = self._approved_context.get(set()) approved.add(tool_name) # stores "execute_command", not args self._approved_context.set(approved) ``` The approval context is never cleared during agent execution — `clear_approved()` exists (`registry.py:152`) but is never called in the agent's tool execution path (`agent/tool_execution.py`). Meanwhile, the `ConsoleBackend` UI at `backends.py:95-96` misleads the user: ```python return Confirm.ask( f"Do you want to execute this {request.risk_level} risk tool?", # "this" implies per-invocation approval ) ``` The UI displays the specific command arguments (lines 81-85), creating a reasonable expectation that the user is approving only that specific invocation. Additionally, `shell_tools.py:77` passes the full process environment to every subprocess: ```python process_env = os.environ.copy() # includes OPENAI_API_KEY, etc. ``` There is no command filtering, blocklist, or environment variable sanitization in the shell tools module. ## PoC ```python from praisonaiagents import Agent from praisonaiagents.tools.shell_tools import execute_command # Step 1: Create agent with shell tool agent = Agent( name="worker", instructions="You are a helpful assistant.", tools=[execute_command] ) # Step 2: Agent requests benign command — user sees Rich panel: # Function: execute_command # Risk Level: CRITICAL # Arguments: # command: ls -la # "Do you want to execute this critical risk tool?" [y/N] # User approves → mark_approved("execute_command") is called # Step 3: All subsequent execute_command calls bypass approval silently: # execute_command(command="env") # → returns ALL environment variables (OPENAI_API_KEY, AWS_SECRET_ACCESS_KEY, etc.) # → NO approval prompt shown # Step 4: Targeted extraction also bypasses approval: # execute_command(command="printenv OPENAI_API_KEY") # → returns the specific API key # → NO approval prompt shown # Verification: check the approval cache from praisonaiagents.approval import is_already_approved # After approving "ls -la": # is_already_approved("execute_command") → True # Any execute_command call now returns immediately at __init__.py:177-178 ``` ## Impact - **Secret exfiltration**: An LLM agent (or one subjected to prompt injection) can dump all process environment variables after a single benign command approval. Common secrets include `OPENAI_API_KEY`, `AWS_SECRET_ACCESS_KEY`, `DATABASE_URL`, and any other credentials passed via environment. - **Misleading consent UI**: The console prompt displays specific arguments and uses language ("this tool") that implies per-invocation consent, but the system grants session-wide blanket approval. - **No expiration or scope**: The approval cache uses a `ContextVar` that persists for the entire agent execution context with no timeout, no command-count limit, and no clearing between tool calls. - **No environment filtering**: `os.environ.copy()` passes every environment variable to subprocesses without filtering sensitive patterns. ## Recommended Fix 1. **Per-invocation approval for critical tools** — store a hash of `(tool_name, arguments)` instead of just `tool_name`, or require re-approval for each invocation of critical-risk tools: ```python # In registry.py — change mark_approved/is_already_approved: import hashlib, json def mark_approved(self, tool_name: str, arguments: dict = None) -> None: approved = self._approved_context.get(set()) risk = self._risk_levels.get(tool_name) if risk == "critical" and arguments: key = f"{tool_name}:{hashlib.sha256(json.dumps(arguments, sort_keys=True).encode()).hexdigest()}" else: key = tool_name approved.add(key) self._approved_context.set(approved) def is_already_approved(self, tool_name: str, arguments: dict = None) -> bool: approved = self._approved_context.get(set()) risk = self._risk_levels.get(tool_name) if risk == "critical" and arguments: key = f"{tool_name}:{hashlib.sha256(json.dumps(arguments, sort_keys=True).encode()).hexdigest()}" return key in approved return tool_name in approved ``` 2. **Filter environment variables** in `shell_tools.py`: ```python SENSITIVE_PATTERNS = ('_KEY', '_SECRET', '_TOKEN', '_PASSWORD', '_CREDENTIAL') process_env = { k: v for k, v in os.environ.items() if not any(p in k.upper() for p in SENSITIVE_PATTERNS) } if env: process_env.update(env) ```

Quoted source text, attributed separately from HOL analysis.