Summary

JobWorkflowExecutor._exec_inline_python() is designed to safely execute inline Python expressions from YAML workflow script: steps using AST validation. The function claims to block dangerous operations by (a) checking all AST nodes against an allowlist, and (b) providing a builtins whitelist that omits import, exec, eval, and open.

The sandbox is broken. The module import allowlist (allowed_modules) explicitly includes 'os', and the AST allowlist permits ast.Import, ast.ImportFrom, ast.Call, and ast.Attribute nodes. This means the following malicious workflow script: step passes all AST validation checks and executes without error.

Attack Scenario

Attacker creates or contributes a YAML workflow file (type: job) with a script: step containing import os; os.system(...). A user or CI pipeline with PRAISONAI_ALLOW_JOB_WORKFLOWS=true executes the workflow via praisonai workflow run malicious.yaml. Arbitrary OS commands execute with the privileges of the calling process.

This is particularly dangerous in multi-tenant or CI environments where YAML workflows may originate from untrusted sources (e.g., downloaded templates, shared repositories, AI-generated workflows).

PoC

Complete instructions, including specific configuration details, to reproduce the vulnerability.

Impact

Root Cause — Lines 364–372:

pythonallowed_modules = {'os', 'datetime', 'time', 'json', 'math', 're', 'collections', 'itertools'} if isinstance(node, ast.Import): for alias in node.names: if alias.name.split('.')[0] not in allowed_modules: return {"ok": False, "error": f"Import of '{alias.name}' not allowed..."}

os is trusted because it is commonly used for path operations (os.path, os.getcwd). However, os.system(), os.popen(), os.execvp(), os.spawn*(), and os._exit() are all accessible once the module is imported, none of which are individually blocked.

The builtins restriction (blocking import) is irrelevant because the code uses a real import statement processed by the Python bytecode compiler — not a import() call.

Proof-of-Concept validation (static — no remote network call made):

pythonimport ast

_ALLOWED_NODES = ( ast.Expression, ast.BoolOp, ast.BinOp, ast.UnaryOp, ast.Compare, ast.IfExp, ast.Constant, ast.Name, ast.Load, ast.Store, ast.Subscript, ast.List, ast.Tuple, ast.Dict, ast.Set, ast.And, ast.Or, ast.Not, ast.Eq, ast.NotEq, ast.Lt, ast.LtE, ast.Gt, ast.GtE, ast.In, ast.NotIn, ast.Add, ast.Sub, ast.Mult, ast.Div, ast.Mod, ast.FloorDiv, ast.USub, ast.UAdd, ast.Call, ast.Attribute, ast.keyword, ast.Starred, ast.Module, ast.Assign, ast.Import, ast.ImportFrom, ast.alias, ) allowed_modules = {'os', 'datetime', 'time', 'json', 'math', 're', 'collections', 'itertools'}