Add Description() to ScanModule (#248)

This abstracts more of the help text into the ScanModule definition,
removing some more of the need for `zgrab2.AddCommand()`

https://github.com/zmap/zgrab2/pull/248

module.go

@@ -48,6 +48,10 @@ type ScanModule interface {
 	// NewScanner is called by the framework for each time an individual scan is specified in the config or on
 	// the command-line. The framework will then call scanner.Init(name, flags).
 	NewScanner() Scanner
+
+	// Description returns a string suitable for use as an overview of this
+	// module within usage text.
+	Description() string
 }
 
 // ScanFlags is an interface which must be implemented by all types sent to

modules/bacnet/scanner.go

@@ -32,7 +32,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("bacnet", "bacnet", "Probe for bacnet", 0xBAC0, &module)
+	_, err := zgrab2.AddCommand("bacnet", "bacnet", module.Description(), 0xBAC0, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -48,6 +48,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns text uses in the help for this module.
+func (module *Module) Description() string {
+	return "Probe for devices that speak Bacnet, commonly used for HVAC control."
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/banner/scanner.go

@@ -42,7 +42,7 @@ type Results struct {
 // RegisterModule is called by modules/banner.go to register the scanner.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("banner", "Banner", "Grab banner by sending probe and match with regexp", 80, &module)
+	_, err := zgrab2.AddCommand("banner", "Banner", module.Description(), 80, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -83,6 +83,11 @@ func (f *Flags) Validate(args []string) error {
 	return nil
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Fetch a raw banner by sending a static probe and checking the result against a regular expression"
+}
+
 // Help returns the module's help string.
 func (f *Flags) Help() string {
 	return ""

modules/dnp3/scanner.go

@@ -30,7 +30,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("dnp3", "dnp3", "Probe for dnp3", 20000, &module)
+	_, err := zgrab2.AddCommand("dnp3", "dnp3", module.Description(), 20000, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -46,6 +46,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for DNP3, a SCADA protocol"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/fox/scanner.go

@@ -30,7 +30,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("fox", "fox", "Probe for Tridium Fox", 1911, &module)
+	_, err := zgrab2.AddCommand("fox", "fox", module.Description(), 1911, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -46,6 +46,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for Tridium Fox"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/ftp/scanner.go

@@ -71,7 +71,7 @@ type Connection struct {
 // RegisterModule registers the ftp zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("ftp", "FTP", "Grab an FTP banner", 21, &module)
+	_, err := zgrab2.AddCommand("ftp", "FTP", module.Description(), 21, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -88,6 +88,11 @@ func (m *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (m *Module) Description() string {
+	return "Grab an FTP banner"
+}
+
 // Validate does nothing in this module.
 func (f *Flags) Validate(args []string) error {
 	return nil

modules/http/scanner.go

@@ -98,6 +98,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Send an HTTP request and read the response, optionally following redirects."
+}
+
 // Validate performs any needed validation on the arguments
 func (flags *Flags) Validate(args []string) error {
 	return nil
@@ -401,7 +406,7 @@ func (scanner *Scanner) Scan(t zgrab2.ScanTarget) (zgrab2.ScanStatus, interface{
 func RegisterModule() {
 	var module Module
 
-	_, err := zgrab2.AddCommand("http", "HTTP Banner Grab", "Grab a banner over HTTP", 80, &module)
+	_, err := zgrab2.AddCommand("http", "HTTP Banner Grab", module.Description(), 80, &module)
 	if err != nil {
 		log.Fatal(err)
 	}

modules/imap/scanner.go

@@ -25,9 +25,10 @@ package imap
 import (
 	"fmt"
 
+	"strings"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/zmap/zgrab2"
-	"strings"
 )
 
 // ScanResults instances are returned by the module's Scan function.
@@ -76,7 +77,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("imap", "imap", "Probe for IMAP", 143, &module)
+	_, err := zgrab2.AddCommand("imap", "imap", module.Description(), 143, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -92,6 +93,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Fetch an IMAP banner, optionally over TLS"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/ipp/scanner.go

@@ -7,6 +7,7 @@ import (
 	"crypto/sha256"
 	"encoding/binary"
 	"errors"
+
 	//"fmt"
 	"io"
 	"io/ioutil"
@@ -40,7 +41,7 @@ var (
 	// TODO: Explain this error
 	ErrVersionNotSupported = errors.New("IPP version not supported")
 
-	Versions = []version{{Major: 2, Minor: 1}, {Major: 2, Minor: 0}, {Major: 1, Minor: 1}, {Major: 1, Minor: 0}}
+	Versions          = []version{{Major: 2, Minor: 1}, {Major: 2, Minor: 0}, {Major: 1, Minor: 1}, {Major: 1, Minor: 0}}
 	AttributesCharset = []byte{0x47, 0x00, 0x12, 0x61, 0x74, 0x74, 0x72, 0x69, 0x62, 0x75, 0x74, 0x65, 0x73, 0x2d, 0x63, 0x68, 0x61, 0x72, 0x73, 0x65, 0x74}
 )
 
@@ -70,9 +71,9 @@ type ScanResults struct {
 	CUPSVersion   string `json:"cups_version,omitempty"`
 
 	Attributes           []*Attribute `json:"attributes,omitempty"`
-	AttributeCUPSVersion string   `json:"attr_cups_version,omitempty"`
+	AttributeCUPSVersion string       `json:"attr_cups_version,omitempty"`
-	AttributeIPPVersions []string `json:"attr_ipp_versions,omitempty"`
+	AttributeIPPVersions []string     `json:"attr_ipp_versions,omitempty"`
-	AttributePrinterURIs []string `json:"attr_printer_uris,omitempty"`
+	AttributePrinterURIs []string     `json:"attr_printer_uris,omitempty"`
 
 	TLSLog *zgrab2.TLSLog `json:"tls,omitempty"`
 }
@@ -117,7 +118,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("ipp", "ipp", "Probe for ipp", 631, &module)
+	_, err := zgrab2.AddCommand("ipp", "ipp", module.Description(), 631, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -133,6 +134,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for printers via IPP"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.
@@ -206,13 +212,13 @@ type Value struct {
 }
 
 type Attribute struct {
-	Name string    `json:"name,omitempty"`
+	Name     string  `json:"name,omitempty"`
-	Values []Value `json:"values,omitempty"`
+	Values   []Value `json:"values,omitempty"`
-	ValueTag byte  `json:"tag,omitempty"`
+	ValueTag byte    `json:"tag,omitempty"`
 }
 
 func shouldReturnAttrs(length, soFar, size, upperBound int) (bool, error) {
-	if soFar + length > size {
+	if soFar+length > size {
 		// Size should never exceed upperBound in practice because of truncation, but this is more general
 		if size >= upperBound {
 			return true, nil
@@ -260,9 +266,9 @@ func readAllAttributes(body []byte, scanner *Scanner) ([]*Attribute, error) {
 	buf := bytes.NewBuffer(body)
 	// Each field of this struct is exported to avoid binary.Read panicking
 	var start struct {
-		Version int16
+		Version    int16
 		StatusCode int16
-		ReqID int32
+		ReqID      int32
 	}
 	// Read in pre-attribute part of body to ignore it
 	if err := binary.Read(buf, binary.BigEndian, &start); err != nil {
@@ -299,7 +305,7 @@ func readAllAttributes(body []byte, scanner *Scanner) ([]*Attribute, error) {
 		}
 		bytesRead += 2
 		// If reading the name would entail reading past body, check whether body was truncated
-		if should, err := shouldReturnAttrs(int(nameLength), bytesRead, len(body), scanner.config.MaxSize * 1024); should {
+		if should, err := shouldReturnAttrs(int(nameLength), bytesRead, len(body), scanner.config.MaxSize*1024); should {
 			// If body was truncated, return all attributes so far without error
 			// Otherwise, return a protocol error because name-length should indicate the
 			// length of the following name when obeying the protocol's encoding
@@ -311,7 +317,7 @@ func readAllAttributes(body []byte, scanner *Scanner) ([]*Attribute, error) {
 		// an additional value for the former, so we read and append another value for that attr
 		if tag == lastTag && nameLength == 0 {
 			attr = attrs[len(attrs)-1]
-		// Otherwise, create a new attribute and read in its name
+			// Otherwise, create a new attribute and read in its name
 		} else {
 			attr = &Attribute{ValueTag: tag}
 			attrs = append(attrs, attr)
@@ -332,7 +338,7 @@ func readAllAttributes(body []byte, scanner *Scanner) ([]*Attribute, error) {
 		}
 		bytesRead += 2
 		// If reading the name would entail reading past body, check whether body was truncated
-		if should, err := shouldReturnAttrs(int(length), bytesRead, len(body), scanner.config.MaxSize * 1024); should {
+		if should, err := shouldReturnAttrs(int(length), bytesRead, len(body), scanner.config.MaxSize*1024); should {
 			// If body was truncated, return all attributes so far without error
 			// Otherwise, return a protocol error because name-length should indicate the
 			// length of the following name when obeying the protocol's encoding
@@ -366,7 +372,7 @@ func (scanner *Scanner) tryReadAttributes(resp *http.Response, scan *scan) *zgra
 	// Therefore, an HTTP Status Code other than 200 indicates the response is not a well-formed IPP response.
 	// RFC 8010 Section 3.4.3 Source: https://tools.ietf.org/html/rfc8010#section-3.4.3
 	if resp.StatusCode != 200 {
-		return zgrab2.NewScanError(zgrab2.SCAN_APPLICATION_ERROR, errors.New("Response returned with status " + resp.Status))
+		return zgrab2.NewScanError(zgrab2.SCAN_APPLICATION_ERROR, errors.New("Response returned with status "+resp.Status))
 	}
 
 	// Reject successful responses which specify non-IPP MIME mediatype (ie: text/html)

modules/modbus/scanner.go

@@ -52,7 +52,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("modbus", "modbus", "Probe for modbus", 502, &module)
+	_, err := zgrab2.AddCommand("modbus", "modbus", module.Description(), 502, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -68,6 +68,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for Modbus devices, usually PLCs as part of a SCADA system"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/mongodb/scanner.go

@@ -1,11 +1,12 @@
 package mongodb
 
 import (
-	"fmt"
-	"encoding/hex"
 	"encoding/binary"
-	"github.com/zmap/zgrab2"
+	"encoding/hex"
+	"fmt"
+
 	log "github.com/sirupsen/logrus"
+	"github.com/zmap/zgrab2"
 	"gopkg.in/mgo.v2/bson"
 )
 
@@ -20,10 +21,10 @@ type Flags struct {
 
 // Scanner implements the zgrab2.Scanner interface
 type Scanner struct {
-	config			*Flags
+	config              *Flags
-	isMasterMsg		[]byte
+	isMasterMsg         []byte
-	buildInfoCommandMsg	[]byte
+	buildInfoCommandMsg []byte
-	buildInfoOpMsg		[]byte
+	buildInfoOpMsg      []byte
 }
 
 // scan holds the state for the scan of an individual target
@@ -42,7 +43,7 @@ func (scan *scan) Close() {
 
 // getCommandMsg returns a mongodb message containing the specified BSON-encoded command.
 // metdata and commandArgs expected to be BSON byte arrays.
-func getCommandMsg(database string, commandName string, metadata []byte, commandArgs []byte) ([]byte) {
+func getCommandMsg(database string, commandName string, metadata []byte, commandArgs []byte) []byte {
 	dblen := len(database) + 1
 	cnlen := len(commandName) + 1
 	mdlen := len(metadata)
@@ -67,8 +68,8 @@ func getCommandMsg(database string, commandName string, metadata []byte, command
 
 // getIsMasterMsg returns a mongodb message containing isMaster command.
 // https://docs.mongodb.com/manual/reference/command/isMaster/
-func getIsMasterMsg() ([]byte) {
+func getIsMasterMsg() []byte {
-	query, err := bson.Marshal(bson.M{ "isMaster": 1 })
+	query, err := bson.Marshal(bson.M{"isMaster": 1})
 	if err != nil {
 		// programmer error
 		log.Fatalf("Invalid BSON: %v", err)
@@ -78,8 +79,8 @@ func getIsMasterMsg() ([]byte) {
 }
 
 // getBuildInfoCommandMsg returns a mongodb message containing a command to retrieve MongoDB build info.
-func getBuildInfoCommandMsg() ([]byte) {
+func getBuildInfoCommandMsg() []byte {
-	metaData, err := bson.Marshal(bson.M{ "buildInfo": 1 })
+	metaData, err := bson.Marshal(bson.M{"buildInfo": 1})
 	if err != nil {
 		// programmer error
 		log.Fatalf("Invalid BSON: %v", err)
@@ -96,7 +97,7 @@ func getBuildInfoCommandMsg() ([]byte) {
 
 // getOpQuery returns a mongodb OP_QUERY message containing the specified BSON-encoded query.
 // query expected to be BSON byte array.
-func getOpQuery(collname string, query []byte) ([]byte) {
+func getOpQuery(collname string, query []byte) []byte {
 	flagslen := 4
 	collname_len := len(collname) + 1
 	nskiplen := 4
@@ -119,7 +120,7 @@ func getOpQuery(collname string, query []byte) ([]byte) {
 
 // getOpMsg returns a mongodb OP_MSG message containing the specified BSON-encoded command.
 // section expected to be BSON byte array.
-func getOpMsg(section []byte) ([]byte) {
+func getOpMsg(section []byte) []byte {
 	flagslen := 4
 	slen := len(section)
 	msglen := MSGHEADER_LEN + flagslen + slen
@@ -134,14 +135,14 @@ func getOpMsg(section []byte) ([]byte) {
 }
 
 // getBuildInfoOpMsg returns a mongodb "OP" message containing query to retrieve MongoDB build info.
-func getBuildInfoOpMsg() ([]byte) {
+func getBuildInfoOpMsg() []byte {
 	// gleaned from tshark
-	section_payload, err := bson.Marshal(bson.M{ "buildinfo": 1, "$db": "admin" })
+	section_payload, err := bson.Marshal(bson.M{"buildinfo": 1, "$db": "admin"})
 	if err != nil {
 		// programmer error
 		log.Fatalf("Invalid BSON: %v", err)
 	}
-	section := make([]byte, len(section_payload) + 1)
+	section := make([]byte, len(section_payload)+1)
 	copy(section[1:], section_payload)
 	op_msg := getOpMsg(section)
 	return op_msg
@@ -149,39 +150,39 @@ func getBuildInfoOpMsg() ([]byte) {
 
 // BuildEnvironment_t holds build environment information returned by scan.
 type BuildEnvironment_t struct {
-	Distmod string `bson:"distmod,omitempty" json:"dist_mod,omitempty"`
+	Distmod    string `bson:"distmod,omitempty" json:"dist_mod,omitempty"`
-	Distarch string `bson:"distarch,omitempty" json:"dist_arch,omitempty"`
+	Distarch   string `bson:"distarch,omitempty" json:"dist_arch,omitempty"`
-	Cc string `bson:"cc,omitempty" json:"cc,omitempty"`
+	Cc         string `bson:"cc,omitempty" json:"cc,omitempty"`
-	CcFlags string `bson:"ccflags,omitempty" json:"cc_flags,omitempty"`
+	CcFlags    string `bson:"ccflags,omitempty" json:"cc_flags,omitempty"`
-	Cxx string `bson:"cxx,omitempty" json:"cxx,omitempty"`
+	Cxx        string `bson:"cxx,omitempty" json:"cxx,omitempty"`
-	CxxFlags string `bson:"cxxflags,omitempty" json:"cxx_flags,omitempty"`
+	CxxFlags   string `bson:"cxxflags,omitempty" json:"cxx_flags,omitempty"`
-	LinkFlags string `bson:"linkflags,omitempty" json:"link_flags,omitempty"`
+	LinkFlags  string `bson:"linkflags,omitempty" json:"link_flags,omitempty"`
 	TargetArch string `bson:"target_arch,omitempty" json:"target_arch,omitempty"`
-	TargetOS string `bson:"target_os,omitempty" json:"target_os,omitempty"`
+	TargetOS   string `bson:"target_os,omitempty" json:"target_os,omitempty"`
 }
 
 // BuildInfo_t holds the data returned by the the buildInfo query
 type BuildInfo_t struct {
-	Version string `bson:"version,omitempty" json:"version,omitempty"`
+	Version          string             `bson:"version,omitempty" json:"version,omitempty"`
-	GitVersion string `bson:"gitVersion,omitempty" json:"git_version,omitempty"`
+	GitVersion       string             `bson:"gitVersion,omitempty" json:"git_version,omitempty"`
 	BuildEnvironment BuildEnvironment_t `bson:"buildEnvironment,omitempty" json:"build_environment,omitempty"`
 }
 
 // IsMaster_t holds the data returned by an isMaster query
 type IsMaster_t struct {
-	IsMaster bool `bson:"ismaster" json:"is_master"`
+	IsMaster                     bool  `bson:"ismaster" json:"is_master"`
-	MaxWireVersion int32 `bson:"maxWireVersion,omitempty" json:"max_wire_version,omitempty"`
+	MaxWireVersion               int32 `bson:"maxWireVersion,omitempty" json:"max_wire_version,omitempty"`
-	MinWireVersion int32 `bson:"minWireVersion,omitempty" json:"min_wire_version,omitempty"`
+	MinWireVersion               int32 `bson:"minWireVersion,omitempty" json:"min_wire_version,omitempty"`
-	MaxBsonObjectSize int32 `bson:"maxBsonObjectSize,omitempty" json:"max_bson_object_size,omitempty"`
+	MaxBsonObjectSize            int32 `bson:"maxBsonObjectSize,omitempty" json:"max_bson_object_size,omitempty"`
-	MaxWriteBatchSize int32 `bson:"maxWriteBatchSize,omitempty" json:"max_write_batch_size,omitempty"`
+	MaxWriteBatchSize            int32 `bson:"maxWriteBatchSize,omitempty" json:"max_write_batch_size,omitempty"`
 	LogicalSessionTimeoutMinutes int32 `bson:"logicalSessionTimeoutMinutes,omitempty" json:"logical_session_timeout_minutes,omitempty"`
-	MaxMessageSizeBytes int32 `bson:"maxMessageSizeBytes,omitempty" json:"max_message_size_bytes,omitempty"`
+	MaxMessageSizeBytes          int32 `bson:"maxMessageSizeBytes,omitempty" json:"max_message_size_bytes,omitempty"`
-	ReadOnly bool `bson:"readOnly" json:"read_only"`
+	ReadOnly                     bool  `bson:"readOnly" json:"read_only"`
 }
 
 // Result holds the data returned by a scan
 type Result struct {
-	IsMaster *IsMaster_t `json:"is_master,omitempty"`
+	IsMaster  *IsMaster_t  `json:"is_master,omitempty"`
 	BuildInfo *BuildInfo_t `json:"build_info,omitempty"`
 }
 
@@ -235,6 +236,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Perform a handshake with a MongoDB server"
+}
+
 // StartScan opens a connection to the target and sets up a scan instance for it.
 func (scanner *Scanner) StartScan(target *zgrab2.ScanTarget) (*scan, error) {
 	conn, err := target.Open(&scanner.config.BaseFlags)
@@ -265,25 +271,25 @@ func getIsMaster(conn *Connection) (*IsMaster_t, error) {
 		return nil, err
 	}
 
-	if len(msg) < doc_offset + 4 {
+	if len(msg) < doc_offset+4 {
 		err = fmt.Errorf("Server truncated message - no query reply (%d bytes: %s)", len(msg), hex.EncodeToString(msg))
 		return nil, err
 	}
-	respFlags := binary.LittleEndian.Uint32(msg[MSGHEADER_LEN:MSGHEADER_LEN + 4])
+	respFlags := binary.LittleEndian.Uint32(msg[MSGHEADER_LEN : MSGHEADER_LEN+4])
-	if respFlags & QUERY_RESP_FAILED != 0 {
+	if respFlags&QUERY_RESP_FAILED != 0 {
 		err = fmt.Errorf("isMaster query failed")
 		return nil, err
 	}
-	doclen := int(binary.LittleEndian.Uint32(msg[doc_offset:doc_offset + 4]))
+	doclen := int(binary.LittleEndian.Uint32(msg[doc_offset : doc_offset+4]))
 	if len(msg[doc_offset:]) < doclen {
 		err = fmt.Errorf("Server truncated BSON reply doc (%d bytes: %s)",
-			  len(msg[doc_offset:]), hex.EncodeToString(msg))
+			len(msg[doc_offset:]), hex.EncodeToString(msg))
 		return nil, err
 	}
 	err = bson.Unmarshal(msg[doc_offset:], &document)
 	if err != nil {
 		err = fmt.Errorf("Server sent invalid BSON reply doc (%d bytes: %s)",
-			  len(msg[doc_offset:]), hex.EncodeToString(msg))
+			len(msg[doc_offset:]), hex.EncodeToString(msg))
 		return nil, err
 	}
 	return document, nil
@@ -309,7 +315,7 @@ func (scanner *Scanner) Scan(target zgrab2.ScanTarget) (zgrab2.ScanStatus, inter
 
 	// Gleaned from wireshark - if "MaxWireVersion" is less than 7, then
 	// "build info" command should be sent in an OP_COMMAND with the query sent
-	// and response retrieved at "metadata" offset. At 7 and above, should 
+	// and response retrieved at "metadata" offset. At 7 and above, should
 	// be sent as an OP_MSG in the "section" field, and response is at "body" offset
 	if result.IsMaster.MaxWireVersion < 7 {
 		query = scanner.buildInfoCommandMsg
@@ -327,15 +333,15 @@ func (scanner *Scanner) Scan(target zgrab2.ScanTarget) (zgrab2.ScanStatus, inter
 		return zgrab2.TryGetScanStatus(err), &result, err
 	}
 
-	if len(msg) < MSGHEADER_LEN + resplen_offset {
+	if len(msg) < MSGHEADER_LEN+resplen_offset {
 		err = fmt.Errorf("Server truncated message - no metadata doc (%d bytes: %s)", len(msg), hex.EncodeToString(msg))
 		return zgrab2.SCAN_PROTOCOL_ERROR, &result, err
 	}
 
-	responselen := int(binary.LittleEndian.Uint32(msg[MSGHEADER_LEN:MSGHEADER_LEN + resplen_offset]))
+	responselen := int(binary.LittleEndian.Uint32(msg[MSGHEADER_LEN : MSGHEADER_LEN+resplen_offset]))
 	if len(msg[MSGHEADER_LEN:]) < responselen {
-		err =  fmt.Errorf("Server truncated BSON response doc (%d bytes: %s)",
+		err = fmt.Errorf("Server truncated BSON response doc (%d bytes: %s)",
-				  len(msg[MSGHEADER_LEN:]), hex.EncodeToString(msg))
+			len(msg[MSGHEADER_LEN:]), hex.EncodeToString(msg))
 		return zgrab2.SCAN_PROTOCOL_ERROR, &result, err
 	}
 	bson.Unmarshal(msg[MSGHEADER_LEN+resp_offset:], &result.BuildInfo)
@@ -346,7 +352,7 @@ func (scanner *Scanner) Scan(target zgrab2.ScanTarget) (zgrab2.ScanStatus, inter
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("mongodb", "mongodb", "Probe for mongodb", 27017, &module)
+	_, err := zgrab2.AddCommand("mongodb", "mongodb", module.Description(), 27017, &module)
 	if err != nil {
 		log.Fatal(err)
 	}

modules/mssql/scanner.go

@@ -12,9 +12,10 @@
 package mssql
 
 import (
+	"strings"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/zmap/zgrab2"
-	"strings"
 )
 
 // ScanResults contains detailed information about each step of the
@@ -68,6 +69,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Perform a handshake for MSSQL databases"
+}
+
 // Validate does nothing in this module.
 func (flags *Flags) Validate(args []string) error {
 	return nil
@@ -172,7 +178,7 @@ func (scanner *Scanner) Scan(target zgrab2.ScanTarget) (zgrab2.ScanStatus, inter
 // RegisterModule is called by modules/mssql.go's init()
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("mssql", "MSSQL", "Grab a mssql handshake", 1433, &module)
+	_, err := zgrab2.AddCommand("mssql", "MSSQL", module.Description(), 1433, &module)
 	if err != nil {
 		log.Fatal(err)
 	}

modules/mysql/scanner.go

@@ -149,7 +149,7 @@ type Scanner struct {
 // RegisterModule is called by modules/mysql.go to register the scanner.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("mysql", "MySQL", "Grab a MySQL handshake", 3306, &module)
+	_, err := zgrab2.AddCommand("mysql", "MySQL", module.Description(), 3306, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -165,6 +165,11 @@ func (m *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (m *Module) Description() string {
+	return "Perform a handshake with a MySQL database"
+}
+
 // Validate validates the flags and returns nil on success.
 func (f *Flags) Validate(args []string) error {
 	return nil

modules/ntp/scanner.go

@@ -815,7 +815,7 @@ type Scanner struct {
 // RegisterModule registers the module with zgrab2
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("ntp", "NTP", "Scan for NTP", 123, &module)
+	_, err := zgrab2.AddCommand("ntp", "NTP", module.Description(), 123, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -831,6 +831,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Scan for NTP"
+}
+
 // Validate checks that the flags are valid
 func (cfg *Flags) Validate(args []string) error {
 	return nil

modules/oracle/scanner.go

@@ -106,7 +106,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("oracle", "oracle", "Probe for oracle", 1521, &module)
+	_, err := zgrab2.AddCommand("oracle", "oracle", module.Description(), 1521, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -122,6 +122,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Perform a handshake with Oracle database servers"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/pop3/scanner.go

@@ -28,9 +28,10 @@ package pop3
 import (
 	"fmt"
 
+	"strings"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/zmap/zgrab2"
-	"strings"
 )
 
 // ScanResults instances are returned by the module's Scan function.
@@ -91,7 +92,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("pop3", "pop3", "Probe for pop3", 110, &module)
+	_, err := zgrab2.AddCommand("pop3", "pop3", module.Description(), 110, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -107,6 +108,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Fetch POP3 banners, optionally over TLS"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/postgres/scanner.go

@@ -16,6 +16,7 @@ import (
 	"strings"
 
 	"encoding/json"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/zmap/zgrab2"
 )
@@ -279,6 +280,11 @@ func (m *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (m *Module) Description() string {
+	return "Perform a handshake with a PostgreSQL server"
+}
+
 // Validate checks the arguments; on success, returns nil.
 func (f *Flags) Validate(args []string) error {
 	return nil
@@ -533,7 +539,7 @@ func (s *Scanner) Scan(t zgrab2.ScanTarget) (status zgrab2.ScanStatus, result in
 // the postgres module with the zgrab2 framework.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("postgres", "Postgres", "Grab a Postgres handshake", 5432, &module)
+	_, err := zgrab2.AddCommand("postgres", "Postgres", module.Description(), 5432, &module)
 	if err != nil {
 		log.Fatal(err)
 	}

modules/redis/scanner.go

@@ -159,7 +159,7 @@ type Result struct {
 // RegisterModule registers the zgrab2 module
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("redis", "redis", "Probe for redis", 6379, &module)
+	_, err := zgrab2.AddCommand("redis", "redis", module.Description(), 6379, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -175,6 +175,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for Redis"
+}
+
 // Validate checks that the flags are valid
 func (flags *Flags) Validate(args []string) error {
 	return nil

modules/siemens/scanner.go

@@ -4,9 +4,10 @@
 package siemens
 
 import (
+	"net"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/zmap/zgrab2"
-	"net"
 )
 
 // Flags holds the command-line configuration for the siemens scan module.
@@ -29,7 +30,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("siemens", "siemens", "Probe for Siemens S7", 102, &module)
+	_, err := zgrab2.AddCommand("siemens", "siemens", module.Description(), 102, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -45,6 +46,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for Siemens S7 devices"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/smb/scanner.go

@@ -32,7 +32,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("smb", "smb", "Probe for smb", 445, &module)
+	_, err := zgrab2.AddCommand("smb", "smb", module.Description(), 445, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -48,6 +48,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Probe for SMB servers (Windows filesharing / SAMBA)"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/smtp/scanner.go

@@ -108,7 +108,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("smtp", "smtp", "Probe for smtp", 25, &module)
+	_, err := zgrab2.AddCommand("smtp", "smtp", module.Description(), 25, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -124,6 +124,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Fetch an SMTP server banner, optionally over TLS"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/ssh.go

@@ -33,7 +33,7 @@ type SSHScanner struct {
 
 func init() {
 	var sshModule SSHModule
-	cmd, err := zgrab2.AddCommand("ssh", "SSH Banner Grab", "Grab a banner over SSH", 22, &sshModule)
+	cmd, err := zgrab2.AddCommand("ssh", "SSH Banner Grab", sshModule.Description(), 22, &sshModule)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -51,6 +51,11 @@ func (m *SSHModule) NewScanner() zgrab2.Scanner {
 	return new(SSHScanner)
 }
 
+// Description returns an overview of this module.
+func (m *SSHModule) Description() string {
+	return "Fetch an SSH server banner and collect key exchange information"
+}
+
 func (f *SSHFlags) Validate(args []string) error {
 	return nil
 }

modules/telnet/scanner.go

@@ -36,7 +36,7 @@ type Scanner struct {
 // RegisterModule registers the zgrab2 module.
 func RegisterModule() {
 	var module Module
-	_, err := zgrab2.AddCommand("telnet", "telnet", "Probe for telnet", 23, &module)
+	_, err := zgrab2.AddCommand("telnet", "telnet", module.Description(), 23, &module)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -52,6 +52,11 @@ func (module *Module) NewScanner() zgrab2.Scanner {
 	return new(Scanner)
 }
 
+// Description returns an overview of this module.
+func (module *Module) Description() string {
+	return "Fetch a telnet banner"
+}
+
 // Validate checks that the flags are valid.
 // On success, returns nil.
 // On failure, returns an error instance describing the error.

modules/tls.go

@@ -19,7 +19,7 @@ type TLSScanner struct {
 
 func init() {
 	var tlsModule TLSModule
-	_, err := zgrab2.AddCommand("tls", "TLS Banner Grab", "Grab banner over TLS", 443, &tlsModule)
+	_, err := zgrab2.AddCommand("tls", "TLS Banner Grab", tlsModule.Description(), 443, &tlsModule)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -33,6 +33,11 @@ func (m *TLSModule) NewScanner() zgrab2.Scanner {
 	return new(TLSScanner)
 }
 
+// Description returns an overview of this module.
+func (m *TLSModule) Description() string {
+	return "Perform a TLS handshake"
+}
+
 func (f *TLSFlags) Validate(args []string) error {
 	return nil
 }