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flutter抓包绕过
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2024-1-19 16:36
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flutter的证书校验
起因：
最近工作上让做个app的复测，把apk发我后，开始尝试挂代理抓包，结果发现抓不到
以为是证书没弄好，想着前几天不是刚导入了吗（雾）。又重新导入了下还是不行。然后各种lsp模块，objection都不行，r0capture也没数据。
然后jadx看了下，全是flutter字样，才想起来和flutter有关。
开始百度（：
然后就开始各种找。https://bbs.kanxue.com/thread-261941.htm
根据上面文章找到关键函数handshake.cc386行
session_verify_cert_chain函数在第356行的ssl_x509.cc中被定义
然后根据https://bbs.kanxue.com/thread-261941.htm 这篇文章特征找，但是这个是32位的，所以在app安装的时候指定32位安装
1 | adb install --abi armeabi-v7a <path to apk> |
接下来就是找
往上翻找
写脚本绕过
32位
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 26 27 28 29 | function hook_ssl_verify_result(address) {Interceptor.attach(address, { onEnter: function(args) { console.log("Disabling SSL validation") }, onLeave: function(retval) { console.log("Retval: " + retval); retval.replace(0x1); } }); }function hookFlutter() { var m = Process.findModuleByName("libflutter.so"); var pattern = "2D E9 F0 4F 85 B0 06 46 50 20 10 70"; var res = Memory.scan(m.base, m.size, pattern, { onMatch: function(address, size){ console.log('[+] ssl_verify_result found at: ' + address.toString()); // Add 0x01 because it's a THUMB function // Otherwise, we would get 'Error: unable to intercept function at 0x9906f8ac; please file a bug' hook_ssl_verify_result(address.add(0x01)); }, onError: function(reason){ console.log('[!] There was an error scanning memory'); }, onComplete: function() { console.log("All done") } });} |
然后启动就可以抓包了
64位
搜索ssl_client
照例往上找
然后就找到了这些
1 2 3 4 5 6 7 8 9 | .text:0000000000596870 FF C3 01 D1 SUB SP, SP, #0x70.text:0000000000596874 FD 7B 01 A9 STP X29, X30, [SP,#0x70+var_60].text:0000000000596878 FC 6F 02 A9 STP X28, X27, [SP,#0x70+var_50].text:000000000059687C FA 67 03 A9 STP X26, X25, [SP,#0x70+var_40].text:0000000000596880 F8 5F 04 A9 STP X24, X23, [SP,#0x70+var_30].text:0000000000596884 F6 57 05 A9 STP X22, X21, [SP,#0x70+var_20].text:0000000000596888 F4 4F 06 A9 STP X20, X19, [SP,#0x70+var_10].text:000000000059688C 08 0A 80 52 MOV W8, #0x50.text:0000000000596890 48 00 00 39 STRB W8, [X2] |
然后写脚本
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 26 27 28 29 | function hook_ssl_verify_result(address) {Interceptor.attach(address, { onEnter: function(args) { console.log("Disabling SSL validation") }, onLeave: function(retval) { console.log("Retval: " + retval); retval.replace(0x1); } }); }function hookFlutter() { var m = Process.findModuleByName("libflutter.so"); var pattern = "FF C3 01 D1 FD 7B 01 A9 FC 6F 02 A9FA 67 03 A9 F8 5F 04 A9 F6 57 05 A9 F4 4F 06 A9 08 0A 80 52 48 00 00 39"; var res = Memory.scan(m.base, m.size, pattern, { onMatch: function(address, size){ console.log('[+] ssl_verify_result found at: ' + address.toString()); // Add 0x01 because it's a THUMB function // Otherwise, we would get 'Error: unable to intercept function at 0x9906f8ac; please file a bug' hook_ssl_verify_result(address.add(0x01)); }, onError: function(reason){ console.log('[!] There was an error scanning memory'); }, onComplete: function() { console.log("All done") } });} |
然后发现报错了
把hook_ssl_verify_result(address.add(0x01))改为hook_ssl_verify_result(address)就可以正常使用了
参考：
https://www.jianshu.com/p/ada10d2976f2
https://mp.weixin.qq.com/s/pXpfXK-Ez0n70f3bqFuuFg
https://bbs.kanxue.com/thread-261941.htm
https://blog.nviso.eu/2019/08/13/intercepting-traffic-from-android-flutter-applications/
以上四篇文章均是和flutter证书校验相关
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VPN不行的 |
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样本哇，好像是工作项目中的，不太能分享，不好意思哈 |
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好的感谢~ |
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