Online Chatroom

Author: @JohnHammond#6971

We are on the web and we are here to chat!

Press the Start button on the top-right to begin this challenge.

Please allow up to 30 seconds for the challenge to become available.

Attachments:

from attachmen `package main

import ( “flag” “io/ioutil” “log” “net/http” “strconv” “strings” “time”

"github.com/gorilla/websocket"
"github.com/rs/cors"

)

var addr = flag.String(“addr”, “0.0.0.0:8080”, “http service address”)

var upgrader = websocket.Upgrader{ CheckOrigin: func(r *http.Request) bool { return true }, }

var chatHistory []string

var onlineUsers = []string{ “User0”, “User1”, “User2”, “User3”, “User4”, }

func echo(w http.ResponseWriter, r *http.Request) { c, err := upgrader.Upgrade(w, r, nil) if err != nil { log.Print(“upgrade:”, err) return } defer c.Close()

for {
	_, message, err := c.ReadMessage()
	if err != nil {
		log.Println("read:", err)
		break
	}
	log.Printf("recv: %s", message)

	if strings.HasPrefix(string(message), "!") {
		switch {
		case strings.HasPrefix(string(message), "!history"):
			indexStr := strings.TrimPrefix(string(message), "!history ")
			index, err := strconv.Atoi(indexStr)
			if err != nil || index < 1 || index > len(chatHistory) {
				c.WriteMessage(websocket.TextMessage, []byte("Error: Please request a valid history index (1 to "+strconv.Itoa(len(chatHistory)-1)+")"))
				continue
			}
			err = c.WriteMessage(websocket.TextMessage, []byte(chatHistory[len(chatHistory)-index]))
			if err != nil {
				log.Println("write:", err)
				break
			}
		case strings.HasPrefix(string(message), "!date"):
			response := "<pre>Server date is: " + time.Now().Format(time.RFC3339) + "</pre>"
			err = c.WriteMessage(websocket.TextMessage, []byte(response))
			if err != nil {
				log.Println("write:", err)
				break
			}
		case strings.HasPrefix(string(message), "!users"):
			response := "<pre>Online users: " + strings.Join(onlineUsers, ", ") + "</pre>"
			err = c.WriteMessage(websocket.TextMessage, []byte(response))
			if err != nil {
				log.Println("write:", err)
				break
			}
		case strings.HasPrefix(string(message), "!help"):
			response := "<pre>Commands:\n" +
				"!write [message]: send a message\n" +
				"!date: get the server date\n" +
				"!users: get the online users\n" +
				"!help: list available commands</pre>"
			err = c.WriteMessage(websocket.TextMessage, []byte(response))
			if err != nil {
				log.Println("write:", err)
				break
			}
		case strings.HasPrefix(string(message), "!write"):
			message = []byte(strings.TrimPrefix(string(message), "!write "))
			chatHistory = append(chatHistory, "User0: " + string(message))
			err = c.WriteMessage(websocket.TextMessage, []byte("User0: "+string(message)))
			if err != nil {
				log.Println("write:", err)
				break
			}
		default:
			response := "Invalid command. Type !help for a list of commands."
			err = c.WriteMessage(websocket.TextMessage, []byte(response))
			if err != nil {
				log.Println("write:", err)
				break
			}
		}
	} else {
		response := "Invalid command. Type !help for a list of commands."
		err = c.WriteMessage(websocket.TextMessage, []byte(response))
		if err != nil {
			log.Println("write:", err)
			break
		}
	}
}

}

func allHistory(w http.ResponseWriter, r *http.Request) { w.Write([]byte(strconv.Itoa(len(chatHistory)-1))) }

func main() { flag.Parse() log.SetFlags(0)

flagData, err := ioutil.ReadFile("flag.txt")
if err != nil {
	log.Fatal("Failed to read flag file:", err)
}
flagStr := string(flagData)
chatHistory = append(chatHistory, "User5: Aha! You're right, I was here before all of you! Here's your flag for finding me: " + flagStr)

extraChatMessages := []string{
	"User4: This chat is awesome!",
	"User1: I agree, it's really cool.",
	"User2: I'm enjoying it too!",
	"User3: Me too! Great conversations happening here.",
	"User1: Wait, has someone been here before us?",
	"User2: Oh hey User0, was it you? You can use !help as a command to learn more :)",
}
chatHistory = append(chatHistory, extraChatMessages...)

mux := http.NewServeMux()

mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
	http.ServeFile(w, r, "index.html")
})

mux.HandleFunc("/chatroom.js", func(w http.ResponseWriter, r *http.Request) {
	http.ServeFile(w, r, "chatroom.js")
})

mux.HandleFunc("/echo", echo)
mux.HandleFunc("/allHistory", allHistory)

handler := cors.Default().Handler(mux)
log.Fatal(http.ListenAndServe(*addr, handler))

}`

In the code i found `func main() { flag.Parse() log.SetFlags(0)

flagData, err := ioutil.ReadFile("flag.txt")
if err != nil {
	log.Fatal("Failed to read flag file:", err)
}
flagStr := string(flagData)
chatHistory = append(chatHistory, "User5: Aha! You're right, I was here before all of you! Here's your flag for finding me: " + flagStr)`

so i tryed

!history Error: Please request a valid history index (1 to 11)

!history 12 User5: Aha! You’re right, I was here before all of you! Here’s your flag for finding me: flag{c398112ed498fa2cacc41433a3e3190b}

Glasses

Author: @JohnHammond#6971

Everything is blurry, I think I need glasses!

Press the Start button on the top-right to begin this challenge.

Connect with:

• http://challenge.nahamcon.com:31468

Please allow up to 30 seconds for the challenge to become available.

This took me a bit of time to find in the html

flag½₧8084e4530cf649814456f2a291eb81e9½―

in the code the space between the paragraphs

flag{8084e4530cf649814456f2a291eb81e9}

Technical Support

Author: @JohnHammond#6971

Want to join the party of GIFs, memes and emoji spam? Or just want to ask a question for technical support regarding any challenges in the CTF?

**This CTF uses support tickets to help handle requests. If you need assistance, please create a ticket with the ctf-open-ticket channel. Do not bother DM-ing organizers or facilitators, they will just tell you to open a ticket. You might find a flag in the ticket channel, though!

Connect here:
Join the Discord!**

on the support page Use this channel to open a support ticket during the NahamCon 2023 CTF! flag{a98373a74abb8c5ebb8f5192e034a91c}

Geosint 1

Head over to https://osint.golf and select chall1 under the NahamCon2023 category. Make sure to read the directions if you are unfamiliar with Geosint/Geoguessr!

Connect here: https://osint.golf

chall1

yes, flag{3e3d01a002db29fec2a5e10ec758b852}

from Google maps 16.320547, 102.825139 Tha Phra, Mueang Khon Kaen District, Khon Kaen 40260, Thailand

Ninety One - not solved

Author: @JohnHammond#6971

I found some more random gibberish text. Why are there so many of these?! (Don’t answer that, I know why…)

@iH<,{|jbRH?L^VjGJH<vn3p7I,x~@1jyt>x?,!YAJr*08P

Thank you to all who put this event on and I look foreword to doing better next year