Added support for templating attachments (#1936)

The following attachment types support template variables: docx, docm, pptx, xlsx, xlsm, txt, html, ics.

models/attachment.go

@@ -1,11 +1,156 @@
 package models
 
+import (
+	"archive/zip"
+	"bytes"
+	"encoding/base64"
+	"io"
+	"io/ioutil"
+	"net/url"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
 // Attachment contains the fields and methods for
 // an email attachment
 type Attachment struct {
-	Id         int64  `json:"-"`
-	TemplateId int64  `json:"-"`
-	Content    string `json:"content"`
-	Type       string `json:"type"`
-	Name       string `json:"name"`
+	Id          int64  `json:"-"`
+	TemplateId  int64  `json:"-"`
+	Content     string `json:"content"`
+	Type        string `json:"type"`
+	Name        string `json:"name"`
+	vanillaFile bool   // Vanilla file has no template variables
+}
+
+// Validate ensures that the provided attachment uses the supported template variables correctly.
+func (a Attachment) Validate() error {
+	vc := ValidationContext{
+		FromAddress: "foo@bar.com",
+		BaseURL:     "http://example.com",
+	}
+	td := Result{
+		BaseRecipient: BaseRecipient{
+			Email:     "foo@bar.com",
+			FirstName: "Foo",
+			LastName:  "Bar",
+			Position:  "Test",
+		},
+		RId: "123456",
+	}
+	ptx, err := NewPhishingTemplateContext(vc, td.BaseRecipient, td.RId)
+	if err != nil {
+		return err
+	}
+	_, err = a.ApplyTemplate(ptx)
+	return err
+}
+
+// ApplyTemplate parses different attachment files and applies the supplied phishing template.
+func (a *Attachment) ApplyTemplate(ptx PhishingTemplateContext) (io.Reader, error) {
+
+	decodedAttachment := base64.NewDecoder(base64.StdEncoding, strings.NewReader(a.Content))
+
+	// If we've already determined there are no template variables in this attachment return it immediately
+	if a.vanillaFile == true {
+		return decodedAttachment, nil
+	}
+
+	// Decided to use the file extension rather than the content type, as there seems to be quite
+	//  a bit of variability with types. e.g sometimes a Word docx file would have:
+	//   "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+	fileExtension := filepath.Ext(a.Name)
+
+	switch fileExtension {
+
+	case ".docx", ".docm", ".pptx", ".xlsx", ".xlsm":
+		// Most modern office formats are xml based and can be unarchived.
+		// .docm and .xlsm files are comprised of xml, and a binary blob for the macro code
+
+		// Zip archives require random access for reading, so it's hard to stream bytes. Solution seems to be to use a buffer.
+		// See https://stackoverflow.com/questions/16946978/how-to-unzip-io-readcloser
+		b := new(bytes.Buffer)
+		b.ReadFrom(decodedAttachment)
+		zipReader, err := zip.NewReader(bytes.NewReader(b.Bytes()), int64(b.Len())) // Create a new zip reader from the file
+
+		if err != nil {
+			return nil, err
+		}
+
+		newZipArchive := new(bytes.Buffer)
+		zipWriter := zip.NewWriter(newZipArchive) // For writing the new archive
+
+		// i. Read each file from the Word document archive
+		// ii. Apply the template to it
+		// iii. Add the templated content to a new zip Word archive
+		a.vanillaFile = true
+		for _, zipFile := range zipReader.File {
+			ff, err := zipFile.Open()
+			if err != nil {
+				return nil, err
+			}
+			defer ff.Close()
+			contents, err := ioutil.ReadAll(ff)
+			if err != nil {
+				return nil, err
+			}
+			subFileExtension := filepath.Ext(zipFile.Name)
+			var tFile string
+			if subFileExtension == ".xml" || subFileExtension == ".rels" { // Ignore other files, e.g binary ones and images
+				// First we look for instances where Word has URL escaped our template variables. This seems to happen when inserting a remote image, converting {{.Foo}} to %7b%7b.foo%7d%7d.
+				// See https://stackoverflow.com/questions/68287630/disable-url-encoding-for-includepicture-in-microsoft-word
+				rx, _ := regexp.Compile("%7b%7b.([a-zA-Z]+)%7d%7d")
+				contents := rx.ReplaceAllFunc(contents, func(m []byte) []byte {
+					d, err := url.QueryUnescape(string(m))
+					if err != nil {
+						return m
+					}
+					return []byte(d)
+				})
+
+				// For each file apply the template.
+				tFile, err = ExecuteTemplate(string(contents), ptx)
+				if err != nil {
+					zipWriter.Close() // Don't use defer when writing files https://www.joeshaw.org/dont-defer-close-on-writable-files/
+					return nil, err
+				}
+				// Check if the subfile changed. We only need this to be set once to know in the future to check the 'parent' file
+				if tFile != string(contents) {
+					a.vanillaFile = false
+				}
+			} else {
+				tFile = string(contents) // Could move this to the declaration of tFile, but might be confusing to read
+			}
+			// Write new Word archive
+			newZipFile, err := zipWriter.Create(zipFile.Name)
+			if err != nil {
+				zipWriter.Close() // Don't use defer when writing files https://www.joeshaw.org/dont-defer-close-on-writable-files/
+				return nil, err
+			}
+			_, err = newZipFile.Write([]byte(tFile))
+			if err != nil {
+				zipWriter.Close()
+				return nil, err
+			}
+		}
+		zipWriter.Close()
+		return bytes.NewReader(newZipArchive.Bytes()), err
+
+	case ".txt", ".html", ".ics":
+		b, err := ioutil.ReadAll(decodedAttachment)
+		if err != nil {
+			return nil, err
+		}
+		processedAttachment, err := ExecuteTemplate(string(b), ptx)
+		if err != nil {
+			return nil, err
+		}
+		if processedAttachment == string(b) {
+			a.vanillaFile = true
+		}
+		return strings.NewReader(processedAttachment), nil
+	default:
+		return decodedAttachment, nil // Default is to simply return the file
+	}
+
 }

models/attachment_test.go

@@ -0,0 +1,82 @@
+package models
+
+import (
+	"bufio"
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/check.v1"
+)
+
+func (s *ModelsSuite) TestAttachment(c *check.C) {
+	ptx := PhishingTemplateContext{
+		BaseRecipient: BaseRecipient{
+			FirstName: "Foo",
+			LastName:  "Bar",
+			Email:     "foo@bar.com",
+			Position:  "Space Janitor",
+		},
+		BaseURL:     "http://testurl.com",
+		URL:         "http://testurl.com/?rid=1234567",
+		TrackingURL: "http://testurl.local/track?rid=1234567",
+		Tracker:     "<img alt='' style='display: none' src='http://testurl.local/track?rid=1234567'/>",
+		From:        "From Address",
+		RId:         "1234567",
+	}
+
+	files, err := ioutil.ReadDir("testdata")
+	if err != nil {
+		log.Fatalf("Failed to open attachment folder 'testdata': %v\n", err)
+	}
+	for _, ff := range files {
+		if !ff.IsDir() && !strings.Contains(ff.Name(), "templated") {
+			fname := ff.Name()
+			fmt.Printf("Checking attachment file -> %s\n", fname)
+			data := readFile("testdata/" + fname)
+			if filepath.Ext(fname) == ".b64" {
+				fname = fname[:len(fname)-4]
+			}
+			a := Attachment{
+				Content: data,
+				Name:    fname,
+			}
+			t, err := a.ApplyTemplate(ptx)
+			c.Assert(err, check.Equals, nil)
+			c.Assert(a.vanillaFile, check.Equals, strings.Contains(fname, "without-vars"))
+			c.Assert(a.vanillaFile, check.Not(check.Equals), strings.Contains(fname, "with-vars"))
+
+			// Verfify template was applied as expected
+			tt, err := ioutil.ReadAll(t)
+			if err != nil {
+				log.Fatalf("Failed to parse templated file '%s': %v\n", fname, err)
+			}
+			templatedFile := base64.StdEncoding.EncodeToString(tt)
+			expectedOutput := readFile("testdata/" + strings.TrimSuffix(ff.Name(), filepath.Ext(ff.Name())) + ".templated" + filepath.Ext(ff.Name())) // e.g text-file-with-vars.templated.txt
+			c.Assert(templatedFile, check.Equals, expectedOutput)
+		}
+	}
+}
+
+func readFile(fname string) string {
+	f, err := os.Open(fname)
+	if err != nil {
+		log.Fatalf("Failed to open file '%s': %v\n", fname, err)
+	}
+	reader := bufio.NewReader(f)
+	content, err := ioutil.ReadAll(reader)
+	if err != nil {
+		log.Fatalf("Failed to read file '%s': %v\n", fname, err)
+	}
+	data := ""
+	if filepath.Ext(fname) == ".b64" {
+		data = string(content)
+	} else {
+		data = base64.StdEncoding.EncodeToString(content)
+	}
+	return data
+}

models/maillog.go

@@ -2,7 +2,6 @@ package models
 
 import (
 	"crypto/rand"
-	"encoding/base64"
 	"errors"
 	"fmt"
 	"io"
@@ -10,7 +9,6 @@ import (
 	"math/big"
 	"net/mail"
 	"os"
-	"strings"
 	"time"
 
 	"github.com/gophish/gomail"
@@ -211,6 +209,7 @@ func (m *MailLog) Generate(msg *gomail.Message) error {
 
 	// Parse remaining templates
 	subject, err := ExecuteTemplate(c.Template.Subject, ptx)
+
 	if err != nil {
 		log.Warn(err)
 	}
@@ -239,12 +238,16 @@ func (m *MailLog) Generate(msg *gomail.Message) error {
 		}
 	}
 	// Attach the files
-	for _, a := range c.Template.Attachments {
-		msg.Attach(func(a Attachment) (string, gomail.FileSetting, gomail.FileSetting) {
+	for i, _ := range c.Template.Attachments {
+		a := &c.Template.Attachments[i]
+		msg.Attach(func(a *Attachment) (string, gomail.FileSetting, gomail.FileSetting) {
 			h := map[string][]string{"Content-ID": {fmt.Sprintf("<%s>", a.Name)}}
 			return a.Name, gomail.SetCopyFunc(func(w io.Writer) error {
-				decoder := base64.NewDecoder(base64.StdEncoding, strings.NewReader(a.Content))
-				_, err = io.Copy(w, decoder)
+				content, err := a.ApplyTemplate(ptx)
+				if err != nil {
+					return err
+				}
+				_, err = io.Copy(w, content)
 				return err
 			}), gomail.SetHeader(h)
 		}(a))

models/template.go

@@ -40,6 +40,12 @@ func (t *Template) Validate() error {
 	if err := ValidateTemplate(t.Text); err != nil {
 		return err
 	}
+	for _, a := range t.Attachments {
+		if err := a.Validate(); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 

models/testdata/calendar-file-with-vars.ics

@@ -0,0 +1,51 @@
+BEGIN:VCALENDAR
+PRODID:-//zoom.us//iCalendar Event//EN
+VERSION:2.0
+CALSCALE:GREGORIAN
+METHOD:PUBLISH
+CLASS:PUBLIC
+BEGIN:VTIMEZONE
+TZID:Europe/London
+TZURL:http://tzurl.org/zoneinfo-outlook/Europe/London
+X-LIC-LOCATION:Europe/London
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0100
+TZNAME:BST
+DTSTART:19700329T010000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0000
+TZNAME:GMT
+DTSTART:19701025T020000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20210306T182251Z
+DTSTART;TZID=Europe/London:20210306T183000
+DTEND;TZID=Europe/London:20210306T190000
+SUMMARY:Gophish Test Calendar
+UID:20210306T182251Z-89336450000@fe80:0:0:0:31:49ff:fec9:f252ens5
+TZID:Europe/London
+DESCRIPTION:Glenn Wilkinson is inviting you to a scheduled Zoom meeting.\
+ n\nJoin Zoom Meeting\n{{.URL}}\n\nMeeting ID: 893 3645 9466\nPasscode: 31337\
+ nOne tap mobile\n+442039017895\,\,89336450000#\,\,\,\,*509879# United Ki
+ ngdom\n+441314601196\,\,89336450000#\,\,\,\,*509879# United Kingdom\n\nD
+ ial by your location\n        +44 203 901 7895 United Kingdom\n        +
+ 44 131 460 1196 United Kingdom\n        +44 203 051 2874 United Kingdom\
+ n        +44 203 481 5237 United Kingdom\n        +44 203 481 5240 Unite
+ d Kingdom\n        +1 253 215 8782 US (Tacoma)\n        +1 301 715 8592 
+ US (Washington DC)\n        +1 312 626 6799 US (Chicago)\n        +1 346
+  248 7799 US (Houston)\n        +1 646 558 8656 US (New York)\n        +
+ 1 669 900 9128 US https://us02web.zoom.us/u/kpXDbMrN\n\n
+LOCATION:{{.URL}}
+BEGIN:VALARM
+TRIGGER:-PT10M
+ACTION:DISPLAY
+DESCRIPTION:Reminder
+END:VALARM
+END:VEVENT
+END:VCALENDAR

models/testdata/calendar-file-with-vars.templated.ics

@@ -0,0 +1,51 @@
+BEGIN:VCALENDAR
+PRODID:-//zoom.us//iCalendar Event//EN
+VERSION:2.0
+CALSCALE:GREGORIAN
+METHOD:PUBLISH
+CLASS:PUBLIC
+BEGIN:VTIMEZONE
+TZID:Europe/London
+TZURL:http://tzurl.org/zoneinfo-outlook/Europe/London
+X-LIC-LOCATION:Europe/London
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0100
+TZNAME:BST
+DTSTART:19700329T010000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0000
+TZNAME:GMT
+DTSTART:19701025T020000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20210306T182251Z
+DTSTART;TZID=Europe/London:20210306T183000
+DTEND;TZID=Europe/London:20210306T190000
+SUMMARY:Gophish Test Calendar
+UID:20210306T182251Z-89336450000@fe80:0:0:0:31:49ff:fec9:f252ens5
+TZID:Europe/London
+DESCRIPTION:Glenn Wilkinson is inviting you to a scheduled Zoom meeting.\
+ n\nJoin Zoom Meeting\nhttp://testurl.com/?rid=1234567\n\nMeeting ID: 893 3645 9466\nPasscode: 31337\
+ nOne tap mobile\n+442039017895\,\,89336450000#\,\,\,\,*509879# United Ki
+ ngdom\n+441314601196\,\,89336450000#\,\,\,\,*509879# United Kingdom\n\nD
+ ial by your location\n        +44 203 901 7895 United Kingdom\n        +
+ 44 131 460 1196 United Kingdom\n        +44 203 051 2874 United Kingdom\
+ n        +44 203 481 5237 United Kingdom\n        +44 203 481 5240 Unite
+ d Kingdom\n        +1 253 215 8782 US (Tacoma)\n        +1 301 715 8592 
+ US (Washington DC)\n        +1 312 626 6799 US (Chicago)\n        +1 346
+  248 7799 US (Houston)\n        +1 646 558 8656 US (New York)\n        +
+ 1 669 900 9128 US https://us02web.zoom.us/u/kpXDbMrN\n\n
+LOCATION:http://testurl.com/?rid=1234567
+BEGIN:VALARM
+TRIGGER:-PT10M
+ACTION:DISPLAY
+DESCRIPTION:Reminder
+END:VALARM
+END:VEVENT
+END:VCALENDAR

models/testdata/html-file-with-vars.html

@@ -0,0 +1,13 @@
+<html>
+<head><title>Page for {{.FirstName}}</title></head>
+
+<body>
+
+Hello {{.FirstName}} {{.LastName}} <p>
+
+
+Click <a href="{{.URL}}">here</a> for a legit link.
+
+</body>
+{{.Tracker}}
+</html>

models/testdata/html-file-with-vars.templated.html

@@ -0,0 +1,13 @@
+<html>
+<head><title>Page for Foo</title></head>
+
+<body>
+
+Hello Foo Bar <p>
+
+
+Click <a href="http://testurl.com/?rid=1234567">here</a> for a legit link.
+
+</body>
+<img alt='' style='display: none' src='http://testurl.local/track?rid=1234567'/>
+</html>

models/testdata/html-file-without-vars.html

@@ -0,0 +1,9 @@
+<html>
+<head><title>There are no variables here.</title></head>
+
+<body>
+
+There are no vars in this file.
+
+</body>
+</html>

models/testdata/html-file-without-vars.templated.html

@@ -0,0 +1,9 @@
+<html>
+<head><title>There are no variables here.</title></head>
+
+<body>
+
+There are no vars in this file.
+
+</body>
+</html>

models/testdata/text-file-with-vars.templated.txt

@@ -0,0 +1,19 @@
+The target's unique ID: 1234567
+
+The target's first name: Foo
+
+The target's last name: Bar
+
+The target's position: Space Janitor
+
+The target's email address: foo@bar.com
+
+The spoofed sender: From Address
+
+The URL to the tracking handler: http://testurl.local/track?rid=1234567
+
+An alias for tracker image: <img alt='' style='display: none' src='http://testurl.local/track?rid=1234567'/>
+
+The phishing URL: http://testurl.com/?rid=1234567
+
+The base URL with the path and rid parameter stripped. Useful for making links to static files: http://testurl.com

models/testdata/text-file-with-vars.txt

@@ -0,0 +1,19 @@
+The target's unique ID: {{.RId}}
+
+The target's first name: {{.FirstName}}
+
+The target's last name: {{.LastName}}
+
+The target's position: {{.Position}}
+
+The target's email address: {{.Email}}
+
+The spoofed sender: {{.From}}
+
+The URL to the tracking handler: {{.TrackingURL}}
+
+An alias for tracker image: {{.Tracker}}
+
+The phishing URL: {{.URL}}
+
+The base URL with the path and rid parameter stripped. Useful for making links to static files: {{.BaseURL}}

models/testdata/text-file-without-vars.templated.txt

@@ -0,0 +1 @@
+There are no variables in this file.

models/testdata/text-file-without-vars.txt

@@ -0,0 +1 @@
+There are no variables in this file.