SSTI Search

search.py

# search.py
# Source https://ctftime.org/writeup/10851

def search(obj, max_depth):
    
    visited_clss = []
    visited_objs = []
    
    def visit(obj, path='obj', depth=0):
        yield path, obj
        
        if depth == max_depth:
            return

        elif isinstance(obj, (int, float, bool, str, bytes)):
            return

        elif isinstance(obj, type):
            if obj in visited_clss:
                return
            visited_clss.append(obj)
            print(obj)

        else:
            if obj in visited_objs:
                return
            visited_objs.append(obj)
        
        # attributes
        for name in dir(obj):
            if name.startswith('__') and name.endswith('__'):
                if name not in  ('__globals__', '__class__', '__self__',
                                 '__weakref__', '__objclass__', '__module__'):
                    continue
            attr = getattr(obj, name)
            yield from visit(attr, '{}.{}'.format(path, name), depth + 1)
        
        # dict values
        if hasattr(obj, 'items') and callable(obj.items):
            try:
                for k, v in obj.items():
                    yield from visit(v, '{}[{}]'.format(path, repr(k)), depth)
            except:
                pass
        
        # items
        elif isinstance(obj, (set, list, tuple, frozenset)):
            for i, v in enumerate(obj):
                yield from visit(v, '{}[{}]'.format(path, repr(i)), depth)
            
    yield from visit(obj)