Files

127 lines
4.1 KiB
Go

package slackwebhook
import (
"bytes"
"context"
"fmt"
"io"
"net/http"
"strings"
"github.com/trufflesecurity/trufflehog/v3/pkg/detectors"
"github.com/trufflesecurity/trufflehog/v3/pkg/pb/detectorspb"
regexp "github.com/wasilibs/go-re2"
)
type Scanner struct {
client *http.Client
detectors.DefaultMultiPartCredentialProvider
}
// Ensure the Scanner satisfies the interface at compile time.
var _ detectors.Detector = (*Scanner)(nil)
var _ detectors.CustomFalsePositiveChecker = (*Scanner)(nil)
var (
defaultClient = detectors.DetectorHttpClientWithNoLocalAddresses
// Make sure that your group is surrounded in boundary characters such as below to reduce false positives.
keyPats = map[string]*regexp.Regexp{
"Slack Service Web Hook": regexp.MustCompile(`(https://hooks\.slack\.com/services/T[A-Z0-9]+/B[A-Z0-9]+/[A-Za-z0-9]{23,25})`),
"Slack Workflow Web Hook ": regexp.MustCompile(`(https://hooks\.slack\.com/workflows/T[A-Z0-9]+/A[A-Z0-9]+/[0-9]{17,19}/[A-Za-z0-9]{23,25})`),
}
)
// Keywords are used for efficiently pre-filtering chunks.
// Use identifiers in the secret preferably, or the provider name.
func (s Scanner) Keywords() []string {
return []string{"hooks.slack.com"}
}
// FromData will find and optionally verify SlackWebhook secrets in a given set of bytes.
func (s Scanner) FromData(ctx context.Context, verify bool, data []byte) (results []detectors.Result, err error) {
dataStr := string(data)
for _, keyPat := range keyPats {
matches := keyPat.FindAllStringSubmatch(dataStr, -1)
for _, match := range matches {
resMatch := strings.TrimSpace(match[1])
s1 := detectors.Result{
DetectorType: detectorspb.DetectorType_SlackWebhook,
Raw: []byte(resMatch),
}
s1.ExtraData = map[string]string{
"rotation_guide": "https://howtorotate.com/docs/tutorials/slack-webhook/",
}
if verify {
client := s.client
if client == nil {
client = defaultClient
}
// We don't want to actually send anything to webhooks we find. To verify them without spamming them, we
// send an intentionally malformed message and look for a particular expected error message.
payload := strings.NewReader(`intentionally malformed JSON from TruffleHog scan`)
req, err := http.NewRequestWithContext(ctx, "POST", resMatch, payload)
if err != nil {
continue
}
req.Header.Add("Content-Type", "application/json")
res, err := client.Do(req)
if err == nil {
defer res.Body.Close()
bodyBytes, err := io.ReadAll(res.Body)
if err != nil {
continue
}
defer res.Body.Close()
switch {
case res.StatusCode >= http.StatusOK && res.StatusCode < http.StatusMultipleChoices:
// Hopefully this never happens - it means we actually sent something to a channel somewhere. But
// we at least know the secret is verified.
s1.Verified = true
case res.StatusCode == http.StatusBadRequest && bytes.Equal(bodyBytes, []byte("invalid_payload")):
s1.Verified = true
case res.StatusCode == http.StatusNotFound || res.StatusCode == http.StatusForbidden:
// Not a real webhook or the owning app's OAuth token has been revoked or the app has been deleted
// You might want to handle this case or log it.
default:
err = fmt.Errorf("unexpected HTTP response status %d: %s", res.StatusCode, bodyBytes)
s1.SetVerificationError(err, resMatch)
}
} else {
s1.SetVerificationError(err, resMatch)
}
}
results = append(results, s1)
}
}
return results, nil
}
func (s Scanner) Type() detectorspb.DetectorType {
return detectorspb.DetectorType_SlackWebhook
}
func (s Scanner) Description() string {
return "Slack webhooks are used to send messages from external sources into Slack channels. If compromised, they can be used to send unauthorized messages."
}
func (s Scanner) IsFalsePositive(result detectors.Result) (bool, string) {
// ignore "https:" as a false positive for slack webhook detector
if strings.Contains(string(result.Raw), "https:") {
return false, ""
}
// back to the default false positive checks
return detectors.IsKnownFalsePositive(string(result.Raw), detectors.DefaultFalsePositives, true)
}