1 files changed, 20 insertions, 0 deletions
diff --git a/main.go b/main.go
index f8955de..2663a1e 100644
--- a/main.go
+++ b/main.go
@@ -148,6 +148,21 @@ func embedScriptInPNG(scriptPath, outPath, imagePath, execPath string) (string,
 	return psCmd, nil
 }
 
+func init() {
+	const usageHeader = `
+offensive security utility that embeds PowerShell scripts into PNG images using pixel-level steganography
+
+author: heqnx - https://heqnx.com
+
+`
+	flag.Usage = func() {
+		fmt.Fprint(os.Stderr, usageHeader)
+		fmt.Fprintf(os.Stderr, "usage of %s:\n", os.Args[0])
+		flag.PrintDefaults()
+	}
+	flag.CommandLine.SetOutput(os.Stderr)
+}
+
 func main() {
 	imagePath := flag.String("image", "", "input png file")
 	scriptPath := flag.String("script", "", "powershell script file to embed")
@@ -155,6 +170,11 @@ func main() {
 	outPath := flag.String("out", "", "output png file")
 	flag.Parse()
 
+	if flag.NFlag() == 0 && flag.NArg() == 0 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
 	if *scriptPath == "" || *outPath == "" || *imagePath == "" || *execPath == "" {
 		fmt.Println("go implementation to embed powershell scripts into png images using steganography")
 		fmt.Println("use the powershell one-liner to decode and iex the embedded script")