20.安卓逆向-frida基础-hook分析调试技巧2-hookDES

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内容参考于：图灵Python学院

本人写的内容纯属胡编乱造，全都是合成造假，仅仅只是为了娱乐，请不要盲目相信。

工具下载：

链接：https://pan.baidu.com/s/1rEEJnt85npn7N38Ai0_F2Q?pwd=6tw3

提取码：6tw3

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上一个内容：19.安卓逆向-frida基础-hook分析调试技巧1-hookMD5

上一个内容里使用Frida hook了MD5算法并尝试了对一个app进行使用MD5hook找参数，本次接着继续

本次hook DES算法

下图是DES两种标准实现

package com.example.course1.suanfa;import android.util.Base64;import java.security.spec.AlgorithmParameterSpec;import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;public class AES {public static String des_1(String args) throws Exception{/*** SecretKeyFactory.getInstance("DES") 获取一个DES* generateSecret初始化DES的加密钥匙，专业术语叫做KEY* 一个des算法需要获取的就死key、iv、明文，有了这些之后就可以对参数模拟加密了*/SecretKey secretKey = SecretKeyFactory.getInstance("DES").generateSecret(new DESKeySpec("123456789".getBytes()));/***  new IvParameterSpec("87654321".getBytes()); IV**/AlgorithmParameterSpec iv = new IvParameterSpec("87654321".getBytes());/*** Cipher.getInstance("DES/CBC/PKCS5Padding"); 加密模式*/Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");/*** cipher.init(1, secretKey, iv); 初始化，1表示加密**/cipher.init(1, secretKey, iv);/***  cipher.update(args.getBytes()); 把明文放到缓存区准备加密*/cipher.update(args.getBytes());/*** cipher.doFinal() 加密*/return Base64.encodeToString(cipher.doFinal(), 0);}public static String des_2(String args) throws Exception{SecretKey secretKey = SecretKeyFactory.getInstance("DES").generateSecret(new DESKeySpec("123456789".getBytes()));AlgorithmParameterSpec iv = new IvParameterSpec("87654321".getBytes());Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");cipher.init(1, secretKey, iv);return Base64.encodeToString(cipher.doFinal(args.getBytes()), 0);}}

Frida hook脚本

function bytesToHex(arr) {var str = "";for (var i = 0; i < arr.length; i++) {var tmp = arr[i];if (tmp < 0) {tmp = (255 + tmp + 1).toString(16);} else {tmp = tmp.toString(16);}if (tmp.length == 1) {tmp = "0" + tmp;}str += tmp;}return str;
}
function bytesToBase64(e) {var base64EncodeChars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';var r, a, c, h, o, t;for (c = e.length, a = 0, r = ''; a < c;) {if (h = 255 & e[a++], a == c) {r += base64EncodeChars.charAt(h >> 2),r += base64EncodeChars.charAt((3 & h) << 4),r += '==';break}if (o = e[a++], a == c) {r += base64EncodeChars.charAt(h >> 2),r += base64EncodeChars.charAt((3 & h) << 4 | (240 & o) >> 4),r += base64EncodeChars.charAt((15 & o) << 2),r += '=';break}t = e[a++],r += base64EncodeChars.charAt(h >> 2),r += base64EncodeChars.charAt((3 & h) << 4 | (240 & o) >> 4),r += base64EncodeChars.charAt((15 & o) << 2 | (192 & t) >> 6),r += base64EncodeChars.charAt(63 & t)}return r
}
function bytesToString(arr) {if (typeof arr === 'string') {return arr;}var str = '',_arr = arr;for (var i = 0; i < _arr.length; i++) {var one = _arr[i].toString(2),v = one.match(/^1+?(?=0)/);if (v && one.length == 8) {var bytesLength = v[0].length;var store = _arr[i].toString(2).slice(7 - bytesLength);for (var st = 1; st < bytesLength; st++) {store += _arr[st + i].toString(2).slice(2);}str += String.fromCharCode(parseInt(store, 2));i += bytesLength - 1;} else {str += String.fromCharCode(_arr[i]);}}return str;
}function main() {Java.perform(function () {var SecretKeyFactory = Java.use("javax.crypto.SecretKeyFactory")SecretKeyFactory.getInstance.overload('java.lang.String').implementation = function(str) {console.log(`算法是----》${str}《------------------------------------------------------------》`)return this.getInstance(str)}// 获取 keyvar DESKeySpec = Java.use("javax.crypto.spec.DESKeySpec")DESKeySpec.$init.overload('[B').implementation = function(str) {console.log(`DESKeySpec.$init.overload--》DES的Key bytesToString：${bytesToString(str)}`)console.log(`DESKeySpec.$init.overload--》DES的key bytesToHexKey：${bytesToHex(str)}`)return this.$init(str)}// 获取 ivvar IvParameterSpec = Java.use("javax.crypto.spec.IvParameterSpec")IvParameterSpec.$init.overload("[B").implementation = function(str) {console.log(`DES IV bytesToString：${bytesToString(str)}`)console.log(`DES IV bytesToHex：${bytesToHex(str)}`)return this.$init(str)}var Cipher = Java.use("javax.crypto.Cipher")Cipher.getInstance.overload('java.lang.String').implementation = function(str) {console.log(`Cipher 加密模式 Cipher.getInstance.overload('java.lang.String')：${str}`)return this.getInstance(str)}Cipher.getInstance.overload('java.lang.String', 'java.lang.String').implementation = function(str1,str2) {console.log(`Cipher 加密模式 Cipher.getInstance.overload('java.lang.String', 'java.lang.String') ：${str1} || ${str2}`)return this.getInstance(str1, str2)}Cipher.update.overload('[B').implementation = function(str) {console.log(`DES 明文  Cipher.update.overload('[B') bytesToString：${bytesToString(str)}`)return this.update(str)}Cipher.update.overload('[B', 'int', 'int').implementation = function(str,i1, i2) {console.log(`DES 明文 Cipher.update.overload('[B', 'int', 'int') ：${bytesToString(str)} 入参2：${i1} 入参3：${i2}`)return this.update(str, i1, i2)}Cipher.doFinal.overload('[B').implementation = function(str) {console.log(`des密文入参 Cipher.doFinal.overload('[B') bytesToString：${bytesToString(str)}`)console.log(`des密文入参 Cipher.doFinal.overload('[B') bytesToHex：${bytesToHex(str)}`)var m = this.doFinal(str)console.log(`des密文返回值 Cipher.doFinal.overload('[B') bytesToHex：${bytesToHex(m)}`)console.log(`des密文返回值 Cipher.doFinal.overload('[B') bytesToBase64：${bytesToBase64(m)}`)return m}Cipher.doFinal.overload().implementation = function() {var m = this.doFinal()console.log(`des密文返回值 Cipher.doFinal.overload() bytesToHex：${bytesToHex(m)}`)console.log(`des密文返回值 Cipher.doFinal.overload() bytesToBase64：${bytesToBase64(m)}`)return m}})
}main()

效果图：加密的key