Added JARM fingerprinting module (#282)

JARM is an active-fingerprinting technique developed by Salesforce. It was released https://github.com/salesforce/jarm and a write-up on it can be found at: https://engineering.salesforce.com/easily-identify-malicious-servers-on-the-internet-with-jarm-e095edac525a

Co-authored-by: Silas Cutler <silas@blacklab.io>

modules/jarm.go

@@ -0,0 +1,7 @@
+package modules
+
+import "github.com/zmap/zgrab2/modules/jarm"
+
+func init() {
+	jarm.RegisterModule()
+}

modules/jarm/scanner.go

@@ -0,0 +1,153 @@
+// Ref: https://github.com/salesforce/jarm
+// https://engineering.salesforce.com/easily-identify-malicious-servers-on-the-internet-with-jarm-e095edac525a?gi=4dd05e2277e4
+package jarm
+
+import (
+	_ "fmt"
+	jarm "github.com/RumbleDiscovery/jarm-go"
+	"github.com/zmap/zgrab2"
+	"io"
+	"log"
+	"net"
+	"strings"
+	"time"
+)
+
+// Flags give the command-line flags for the banner module.
+type Flags struct {
+	zgrab2.BaseFlags
+	MaxTries int `long:"max-tries" default:"1" description:"Number of tries for timeouts and connection errors before giving up."`
+}
+
+// Module is the implementation of the zgrab2.Module interface.
+type Module struct {
+}
+
+// Scanner is the implementation of the zgrab2.Scanner interface.
+type Scanner struct {
+	config *Flags
+}
+
+type Results struct {
+	Fingerprint string `json:"fingerprint"`
+	error       string `json:"error,omitempty"`
+}
+
+// RegisterModule is called by modules/banner.go to register the scanner.
+func RegisterModule() {
+	var module Module
+	_, err := zgrab2.AddCommand("jarm", "jarm", module.Description(), 443, &module)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+// NewFlags returns a new default flags object.
+func (m *Module) NewFlags() interface{} {
+	return new(Flags)
+}
+
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Send TLS requiests and generate a JARM fingerprint"
+}
+
+// GetName returns the Scanner name defined in the Flags.
+func (scanner *Scanner) GetName() string {
+	return scanner.config.Name
+}
+
+// GetPort returns the port being scanned.
+func (scanner *Scanner) GetPort() uint {
+	return scanner.config.Port
+}
+
+// GetTrigger returns the Trigger defined in the Flags.
+func (scanner *Scanner) GetTrigger() string {
+	return scanner.config.Trigger
+}
+
+// Protocol returns the protocol identifier of the scan.
+func (scanner *Scanner) Protocol() string {
+	return "jarm"
+}
+
+// InitPerSender initializes the scanner for a given sender.
+func (scanner *Scanner) InitPerSender(senderID int) error {
+	return nil
+}
+
+// NewScanner returns a new Scanner object.
+func (m *Module) NewScanner() zgrab2.Scanner {
+	return new(Scanner)
+}
+
+// Validate validates the flags and returns nil on success.
+func (f *Flags) Validate(args []string) error {
+	return nil
+}
+
+// Help returns the module's help string.
+func (f *Flags) Help() string {
+	return ""
+}
+
+// Init initializes the Scanner with the command-line flags.
+func (scanner *Scanner) Init(flags zgrab2.ScanFlags) error {
+	f, _ := flags.(*Flags)
+	scanner.config = f
+	return nil
+}
+
+func (scanner *Scanner) Scan(target zgrab2.ScanTarget) (zgrab2.ScanStatus, interface{}, error) {
+	// Stores raw hashes returned from parsing each protocols Hello message
+	rawhashes := []string{}
+
+	// Stores final module results
+	r := Results{}
+
+	// Loop through each Probe type
+	for _, probe := range jarm.GetProbes(target.Host(), int(scanner.GetPort())) {
+		data := jarm.BuildProbe(probe)
+
+		var (
+			conn net.Conn
+			err  error
+			ret  []byte
+		)
+		conn, err = target.Open(&scanner.config.BaseFlags)
+		if err != nil {
+			return zgrab2.TryGetScanStatus(err), nil, err
+		}
+
+		_, err = conn.Write([]byte(data))
+		if err != nil {
+			rawhashes = append(rawhashes, "")
+			conn.Close()
+			continue
+		}
+
+		// ret, err = zgrab2.ReadAvailable(conn)
+		ret, err = zgrab2.ReadAvailableWithOptions(conn, 1484, 500*time.Millisecond, 0, 1484)
+		if err != io.EOF && err != nil {
+			rawhashes = append(rawhashes, "")
+			conn.Close()
+			continue
+		}
+
+		ans, err := jarm.ParseServerHello(ret, probe)
+		if err != nil {
+			rawhashes = append(rawhashes, "")
+			conn.Close()
+			continue
+		}
+
+		rawhashes = append(rawhashes, string(ans))
+		conn.Close()
+
+	}
+
+	fprint := jarm.RawHashToFuzzyHash(strings.Join(rawhashes, ","))
+	r.Fingerprint = string(fprint)
+	return zgrab2.SCAN_SUCCESS, &r, nil
+}