前言:
♛ frida hook android Android 逆向神器
前几天在学习 Android 逆向的时候发现了一个神器:通过 frida hook 我们可以 “劫持” 一些函数 为我们所用, 今天就和大家上手一个 加密函数的劫持 让打印出:
- 加密秘钥
- 密文
效果如下:可以很直观的看出 加密算法以及秘钥
文章来源:https://www.toymoban.com/news/detail-682359.html
准备工作:
安装运行环境:(因为我这里都装过来 你们自己对照着来)
- python 环境
C:\Users\Administrator>python --version Python 3.10.6
- frida
C:\Users\Administrator>pip install frida Requirement already satisfied: frida in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (16.1.3) Requirement already satisfied: typing-extensions in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida) (4.7.1) [notice] A new release of pip available: 22.2.1 -> 23.2.1 [notice] To update, run: python.exe -m pip install --upgrade pip C:\Users\Administrator>frida usage: frida [options] target frida: error: target must be specified
- firda-tools
C:\Users\Administrator>pip install frida-tools Requirement already satisfied: frida-tools in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (12.2.1) Requirement already satisfied: prompt-toolkit<4.0.0,>=2.0.0 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida-tools) (3.0.39) Requirement already satisfied: colorama<1.0.0,>=0.2.7 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida-tools) (0.4.6) Requirement already satisfied: pygments<3.0.0,>=2.0.2 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida-tools) (2.15.1) Requirement already satisfied: frida<17.0.0,>=16.0.9 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida-tools) (16.1.3) Requirement already satisfied: typing-extensions in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from frida<17.0.0,>=16.0.9->frida-tools) (4.7.1) Requirement already satisfied: wcwidth in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from prompt-toolkit<4.0.0,>=2.0.0->frida-tools) (0.2.6) [notice] A new release of pip available: 22.2.1 -> 23.2.1 [notice] To update, run: python.exe -m pip install --upgrade pip
- 下载一个 frida server Releases · frida/frida · GitHub
下载地址: https://github.com/frida/frida/releases
因为 我用的是模拟器所有下载这个版本,可以使用 命令查看对于的类型:
C:\Users\Administrator>adb shell getprop ro.product.cpu.abi x86_64
- adb
C:\Users\Administrator>adb devices List of devices attached emulator-5558 device
实操上手:
⒈建立注入环境:运行 frida server (不要关闭)
把刚刚下载的 解压发送到 手机 /data/local/ 目录下, 我这里重命名为 f86(应为一些加壳软件会监测是否使用 frifa)
执行 f86, 记得要给权限!chmod 777 f86
C:\Users\Administrator>adb shell star2qltechn:/ $ su star2qltechn:/ # cd /data/lcoal /system/bin/sh: cd: /data/lcoal: No such file or directory 2|star2qltechn:/ # cd /data/local star2qltechn:/data/local # ls cfg-zeiag f86 file-cache temp-zeiag tmp traces star2qltechn:/data/local # chmod 777 f86 star2qltechn:/data/local # su star2qltechn:/data/local # ./f86
2 建立端口转发 一共两个端口 (不要关闭)
- adb forward tcp:27043 tcp:27043
- adb forward tcp:27042 tcp:27042
C:\Users\Administrator>adb forward tcp:27043 tcp:27043 27043 C:\Users\Administrator>adb forward tcp:27042 tcp:27042 27042
3 运行我们的 hook.js 代码 (不要关闭)
frida -U -F -l C:\Users\Administrator\Desktop\py\hook.js
- -U 指的的我们的 USB设备
- -F 指的是我们最手机 最上层运行的APP
- -l 指定我们脚本路径
运行这App的时候 跑起来我们的脚本
4 奇迹就发生了
hook.js 脚本
var N_ENCRYPT_MODE = 1 var N_DECRYPT_MODE = 2 function showStacks() { var Exception = Java.use("java.lang.Exception"); var ins = Exception.$new("Exception"); var straces = ins.getStackTrace(); if (undefined == straces || null == straces) { return; } console.log("============================= Stack strat======================="); console.log(""); for (var i = 0; i < straces.length; i++) { var str = " " + straces[i].toString(); console.log(str); } console.log(""); console.log("============================= Stack end=======================\r\n"); Exception.$dispose(); } //工具相关函数 var base64EncodeChars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', base64DecodeChars = new Array((-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), (-1), 62, (-1), (-1), (-1), 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, (-1), (-1), (-1), (-1), (-1), (-1), (-1), 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, (-1), (-1), (-1), (-1), (-1), (-1), 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, (-1), (-1), (-1), (-1), (-1)); function stringToBase64(e) { var r, a, c, h, o, t; for (c = e.length, a = 0, r = ''; a < c;) { if (h = 255 & e.charCodeAt(a++), a == c) { r += base64EncodeChars.charAt(h >> 2), r += base64EncodeChars.charAt((3 & h) << 4), r += '=='; break } if (o = e.charCodeAt(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.charCodeAt(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 base64ToString(e) { var r, a, c, h, o, t, d; for (t = e.length, o = 0, d = ''; o < t;) { do r = base64DecodeChars[255 & e.charCodeAt(o++)]; while (o < t && r == -1); if (r == -1) break; do a = base64DecodeChars[255 & e.charCodeAt(o++)]; while (o < t && a == -1); if (a == -1) break; d += String.fromCharCode(r << 2 | (48 & a) >> 4); do { if (c = 255 & e.charCodeAt(o++), 61 == c) return d; c = base64DecodeChars[c] } while (o < t && c == -1); if (c == -1) break; d += String.fromCharCode((15 & a) << 4 | (60 & c) >> 2); do { if (h = 255 & e.charCodeAt(o++), 61 == h) return d; h = base64DecodeChars[h] } while (o < t && h == -1); if (h == -1) break; d += String.fromCharCode((3 & c) << 6 | h) } return d } function hexToBase64(str) { return base64Encode(String.fromCharCode.apply(null, str.replace(/\r|\n/g, "").replace(/([\da-fA-F]{2}) ?/g, "0x$1 ").replace(/ +$/, "").split(" "))); } function base64ToHex(str) { for (var i = 0, bin = base64Decode(str.replace(/[ \r\n]+$/, "")), hex = []; i < bin.length; ++i) { var tmp = bin.charCodeAt(i).toString(16); if (tmp.length === 1) tmp = "0" + tmp; hex[hex.length] = tmp; } return hex.join(""); } function hexToBytes(str) { var pos = 0; var len = str.length; if (len % 2 != 0) { return null; } len /= 2; var hexA = new Array(); for (var i = 0; i < len; i++) { var s = str.substr(pos, 2); var v = parseInt(s, 16); hexA.push(v); pos += 2; } return hexA; } function bytesToHex(arr) { var str = ''; var k, j; for (var i = 0; i < arr.length; i++) { k = arr[i]; j = k; if (k < 0) { j = k + 256; } if (j < 16) { str += "0"; } str += j.toString(16); } return str; } function stringToHex(str) { var val = ""; for (var i = 0; i < str.length; i++) { if (val == "") val = str.charCodeAt(i).toString(16); else val += str.charCodeAt(i).toString(16); } return val } function stringToBytes(str) { var ch, st, re = []; for (var i = 0; i < str.length; i++) { ch = str.charCodeAt(i); st = []; do { st.push(ch & 0xFF); ch = ch >> 8; } while (ch); re = re.concat(st.reverse()); } return re; } //将byte[]转成String的方法 function bytesToString(arr) { var str = ''; arr = new Uint8Array(arr); for (var i in arr) { str += String.fromCharCode(arr[i]); } return str; } function bytesToBase64(e) { 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 base64ToBytes(e) { var r, a, c, h, o, t, d; for (t = e.length, o = 0, d = []; o < t;) { do r = base64DecodeChars[255 & e.charCodeAt(o++)]; while (o < t && r == -1); if (r == -1) break; do a = base64DecodeChars[255 & e.charCodeAt(o++)]; while (o < t && a == -1); if (a == -1) break; d.push(r << 2 | (48 & a) >> 4); do { if (c = 255 & e.charCodeAt(o++), 61 == c) return d; c = base64DecodeChars[c] } while (o < t && c == -1); if (c == -1) break; d.push((15 & a) << 4 | (60 & c) >> 2); do { if (h = 255 & e.charCodeAt(o++), 61 == h) return d; h = base64DecodeChars[h] } while (o < t && h == -1); if (h == -1) break; d.push((3 & c) << 6 | h) } return d } //stringToBase64 stringToHex stringToBytes //base64ToString base64ToHex base64ToBytes // hexToBase64 hexToBytes // bytesToBase64 bytesToHex bytesToString Java.perform(function () { var secretKeySpec = Java.use('javax.crypto.spec.SecretKeySpec'); secretKeySpec.$init.overload('[B', 'java.lang.String').implementation = function (a, b) { showStacks(); var result = this.$init(a, b); console.log("======================================"); console.log("算法名:" + b + "|str密钥:" + bytesToString(a)); console.log("算法名:" + b + "|Hex密钥:" + bytesToHex(a)); return result; } var DESKeySpec = Java.use('javax.crypto.spec.DESKeySpec'); DESKeySpec.$init.overload('[B').implementation = function (a) { showStacks(); var result = this.$init(a); console.log("======================================"); var bytes_key_des = this.getKey(); console.log("des密钥 |str " + bytesToString(bytes_key_des)); console.log("des密钥 |hex " + bytesToHex(bytes_key_des)); return result; } DESKeySpec.$init.overload('[B', 'int').implementation = function (a, b) { showStacks(); var result = this.$init(a, b); console.log("======================================"); var bytes_key_des = this.getKey(); console.log("des密钥 |str " + bytesToString(bytes_key_des)); console.log("des密钥 |hex " + bytesToHex(bytes_key_des)); return result; } var mac = Java.use('javax.crypto.Mac'); mac.getInstance.overload('java.lang.String').implementation = function (a) { showStacks(); var result = this.getInstance(a); console.log("======================================"); console.log("算法名:" + a); return result; } mac.update.overload('[B').implementation = function (a) { //showStacks(); this.update(a); console.log("======================================"); console.log("update:" + bytesToString(a)) } mac.update.overload('[B', 'int', 'int').implementation = function (a, b, c) { //showStacks(); this.update(a, b, c) console.log("======================================"); console.log("update:" + bytesToString(a) + "|" + b + "|" + c); } mac.doFinal.overload().implementation = function () { //showStacks(); var result = this.doFinal(); console.log("======================================"); console.log("doFinal结果: |str :" + bytesToString(result)); console.log("doFinal结果: |hex :" + bytesToHex(result)); console.log("doFinal结果: |base64 :" + bytesToBase64(result)); return result; } mac.doFinal.overload('[B').implementation = function (a) { //showStacks(); var result = this.doFinal(a); console.log("======================================"); console.log("doFinal参数: |str :" + bytesToString(a)); console.log("doFinal结果: |str :" + bytesToString(result)); console.log("doFinal结果: |hex :" + bytesToHex(result)); console.log("doFinal结果: |base64 :" + bytesToBase64(result)); return result; } var md = Java.use('java.security.MessageDigest'); md.getInstance.overload('java.lang.String', 'java.lang.String').implementation = function (a, b) { //showStacks(); console.log("======================================"); console.log("算法名:" + a); return this.getInstance(a, b); } md.getInstance.overload('java.lang.String').implementation = function (a) { //showStacks(); console.log("======================================"); console.log("算法名:" + a); return this.getInstance(a); } md.update.overload('[B').implementation = function (a) { //showStacks(); console.log("======================================"); console.log("update:" + bytesToString(a)) return this.update(a); } md.update.overload('[B', 'int', 'int').implementation = function (a, b, c) { //showStacks(); console.log("======================================"); console.log("update:" + bytesToString(a) + "|" + b + "|" + c); return this.update(a, b, c); } md.digest.overload().implementation = function () { //showStacks(); console.log("======================================"); var result = this.digest(); console.log("digest结果:" + bytesToHex(result)); console.log("digest结果:" + bytesToBase64(result)); return result; } md.digest.overload('[B').implementation = function (a) { //showStacks(); console.log("======================================"); console.log("digest参数:" + bytesToString(a)); var result = this.digest(a); console.log("digest结果:" + bytesToHex(result)); console.log("digest结果:" + bytesToBase64(result)); return result; } var ivParameterSpec = Java.use('javax.crypto.spec.IvParameterSpec'); ivParameterSpec.$init.overload('[B').implementation = function (a) { //showStacks(); var result = this.$init(a); console.log("======================================"); console.log("iv向量: |str:" + bytesToString(a)); console.log("iv向量: |hex:" + bytesToHex(a)); return result; } var cipher = Java.use('javax.crypto.Cipher'); cipher.getInstance.overload('java.lang.String').implementation = function (a) { //showStacks(); var result = this.getInstance(a); console.log("======================================"); console.log("模式填充:" + a); return result; } cipher.init.overload('int', 'java.security.Key').implementation = function (a, b) { //showStacks(); var result = this.init(a, b); console.log("======================================"); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.init.overload('int', 'java.security.cert.Certificate').implementation = function (a, b) { //showStacks(); var result = this.init(a, b); console.log("======================================"); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } return result; } cipher.init.overload('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec').implementation = function (a, b, c) { //showStacks(); var result = this.init(a, b, c); console.log("======================================"); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.init.overload('int', 'java.security.cert.Certificate', 'java.security.SecureRandom').implementation = function (a, b, c) { //showStacks(); var result = this.init(a, b, c); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } return result; } cipher.init.overload('int', 'java.security.Key', 'java.security.SecureRandom').implementation = function (a, b, c) { //showStacks(); var result = this.init(a, b, c); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.init.overload('int', 'java.security.Key', 'java.security.AlgorithmParameters').implementation = function (a, b, c) { //showStacks(); var result = this.init(a, b, c); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.init.overload('int', 'java.security.Key', 'java.security.AlgorithmParameters', 'java.security.SecureRandom').implementation = function (a, b, c, d) { //showStacks(); var result = this.init(a, b, c, d); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.init.overload('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec', 'java.security.SecureRandom').implementation = function (a, b, c, d) { //showStacks(); var result = this.update(a, b, c, d); if (N_ENCRYPT_MODE == a) { console.log("init | 加密模式"); } else if(N_DECRYPT_MODE == a) { console.log("init | 解密模式"); } var bytes_key = b.getEncoded(); console.log("init key:" + "|str密钥:" + bytesToString(bytes_key)); console.log("init key:" + "|Hex密钥:" + bytesToHex(bytes_key)); return result; } cipher.update.overload('[B').implementation = function (a) { //showStacks(); var result = this.update(a); console.log("======================================"); console.log("update:" + bytesToString(a)); return result; } cipher.update.overload('[B', 'int', 'int').implementation = function (a, b, c) { //showStacks(); var result = this.update(a, b, c); console.log("======================================"); console.log("update:" + bytesToString(a) + "|" + b + "|" + c); return result; } cipher.doFinal.overload().implementation = function () { //showStacks(); var result = this.doFinal(); console.log("======================================"); console.log("doFinal结果: |str :" + bytesToString(result)); console.log("doFinal结果: |hex :" + bytesToHex(result)); console.log("doFinal结果: |base64 :" + bytesToBase64(result)); return result; } cipher.doFinal.overload('[B').implementation = function (a) { //showStacks(); var result = this.doFinal(a); console.log("======================================"); console.log("doFinal参数: |str :" + bytesToString(a)); console.log("doFinal结果: |str :" + bytesToString(result)); console.log("doFinal结果: |hex :" + bytesToHex(result)); console.log("doFinal结果: |base64 :" + bytesToBase64(result)); return result; } var x509EncodedKeySpec = Java.use('java.security.spec.X509EncodedKeySpec'); x509EncodedKeySpec.$init.overload('[B').implementation = function (a) { //showStacks(); var result = this.$init(a); console.log("======================================"); console.log("RSA密钥:" + bytesToBase64(a)); return result; } var rSAPublicKeySpec = Java.use('java.security.spec.RSAPublicKeySpec'); rSAPublicKeySpec.$init.overload('java.math.BigInteger', 'java.math.BigInteger').implementation = function (a, b) { //showStacks(); var result = this.$init(a, b); console.log("======================================"); //console.log("RSA密钥:" + bytesToBase64(a)); console.log("RSA密钥N:" + a.toString(16)); console.log("RSA密钥E:" + b.toString(16)); return result; } var KeyPairGenerator = Java.use('java.security.KeyPairGenerator'); KeyPairGenerator.generateKeyPair.implementation = function () { //showStacks(); var result = this.generateKeyPair(); console.log("======================================"); var str_private = result.getPrivate().getEncoded(); var str_public = result.getPublic().getEncoded(); console.log("公钥 |hex" + bytesToHex(str_public)); console.log("私钥 |hex" + bytesToHex(str_private)); return result; } KeyPairGenerator.genKeyPair.implementation = function () { //showStacks(); var result = this.genKeyPair(); console.log("======================================"); var str_private = result.getPrivate().getEncoded(); var str_public = result.getPublic().getEncoded(); console.log("公钥 |hex" + bytesToHex(str_public)); console.log("私钥 |hex" + bytesToHex(str_private)); return result; } });
总结:
使用 frida hook 的原理, 是直接劫持java加密函数, 不需要去逆向代码直接, 效率很高!
对于使用 java 原生开发的应用 效率很高! 但是相对于 flutter 开发的应用效果就比较差了
后面抽空研究研究 fiida 在 flutter 身上的新姿势文章来源地址https://www.toymoban.com/news/detail-682359.html
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