quesiton 3 and 4

week03/easy/client.py

@@ -0,0 +1,22 @@
+import socket
+
+# Fill in the right target here
+HOST = 'this.is.not.a.valid.domain'  # TODO
+PORT = 0  # TODO
+
+
+def get_flag():
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+    s.connect((HOST, PORT))
+    sf = s.makefile('rw')  # we use a file abstraction for the sockets
+
+    message1 = sf.readline().rstrip('\n')
+    # TODO
+
+    sf.close()
+    s.close()
+
+
+if __name__ == '__main__':
+    get_flag()

week03/easy/client_ans.py

@@ -0,0 +1,51 @@
+import socket
+
+# Updated connection details
+HOST = "netsec.net.in.tum.de"
+PORT = 20103
+
+
+def get_flag():
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+    s.connect((HOST, PORT))
+    sf = s.makefile("rw")  # we use a file abstraction for the sockets
+
+    full_message = []
+    collecting = False
+    while True:
+        try:
+            message = sf.readline()
+            if not message:
+                break
+
+            message = message.rstrip("\n")
+            print(f"Server says: {message}")
+
+            if "team number" in message.lower():
+                sf.write("153\n")
+                sf.flush()
+            elif "In this challenge" in message:
+                collecting = True
+                full_message = [message]
+            elif collecting:
+                full_message.append(message)
+                if "solution" in message.lower():
+                    answer = '[("192.168.0.126", "8.8.8.8", "udp", 53836, 53), ("192.168.0.126", "31.192.117.132", "tcp", 41160, 80), ("73.73.73.73", "192.168.0.20", "tcp", 38451, 23), ("192.168.0.126", "54.54.54.54", "tcp", 57020, 25)]'
+                    sf.write(answer + "\n")
+                    sf.flush()
+                    collecting = False
+                    full_message = []
+
+        except socket.timeout:
+            continue
+        except (EOFError, ConnectionError) as e:
+            print(f"Connection error: {e}")
+            break
+
+    sf.close()
+    s.close()
+
+
+if __name__ == "__main__":
+    get_flag()

week03/hard/client.py

@@ -0,0 +1,32 @@
+import socket
+
+# Fill in the right target here
+HOST = "netsec.net.in.tum.de"
+PORT = 20203
+
+
+def create_packet(src_ip, dst_ip, protocol, src_port, dst_port) -> str:
+    return f"{src_ip},{dst_ip},{protocol},{src_port},{dst_port}"
+
+
+def get_flag():
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+    s.connect((HOST, PORT))
+    sf = s.makefile("rw")  # we use a file abstraction for the sockets
+    # TODO
+    src_ip = "161.40.12.151"
+    dst_ip = "10.0.0.1"
+    protocol = "TCP"
+    src_port = 7331
+    dst_port = 1337
+    packet = create_packet(src_ip, dst_ip, protocol, src_port, dst_port)
+    print(f"Sending packet: {packet}")
+    sf.write(packet + "\n")
+    sf.flush()
+    response = sf.readline().strip()
+    print(f"Server response: {response}")
+
+
+if __name__ == "__main__":
+    get_flag()