目前 bfinject 的项目源码仅支持 Dylib 注入的系统为 iOS 11.0 - 11.1.2, 但是现在手头有一台最新越狱的 iOS 11.3，那么怎样使用 bfinject 来脱壳呢？

安装 bfinject

源码地址：https://github.com/BishopFox/bfinject

Electra 越狱用户：

下载 bfinject 的 tar 压缩包，https://github.com/BishopFox/bfinject/raw/master/bfinject.tar

安装后运行

bash bfinject

会报错：

[!] Unknown jailbreak. Aborting.

分析 Unknown jailbrek 报错原因

查看源码：

#

# Detect LiberiOS vs Electra

#

if[ -f /bootstrap/inject_criticald ];then

# This is Electra

echo"[+] Electra detected."

cp jtool.liberios /bootstrap/usr/local/bin/

chmod +x /bootstrap/usr/local/bin/jtool.liberios

JTOOL=/bootstrap/usr/local/bin/jtool.liberios

cp bfinject4realz /bootstrap/usr/local/bin/

INJECTOR=/bootstrap/usr/local/bin/bfinject4realz

elif[ -f /jb/usr/local/bin/jtool ];then

# This is LiberiOS

echo"[+] Liberios detected"

    JTOOL=jtool

INJECTOR=`pwd`/bfinject4realz

else

echo"[!] Unknown jailbreak. Aborting."

exit1

fi

目前最新的 Electra 越狱后系统里找不到文件路径：/bootstrap/inject_criticald，搜索一下inject_reiticald确实存在该文件。

原来如此，bootstrap 目录名更改为 electra 了，

tree-flys-iPhone-7:~ root# ls /electra/

amfid_payload.dylib  helloworld  inject_criticald  jailbreakd  jailbreakd_client  libjailbreak.dylib  pspawn_payload.dylib

FIX 1

考虑到向低版本 iOS 兼容性，尽量减少修改源代码

创建软连接

ln -s /electra /bootstrap

手动创建代码中的文件夹

mkdir /bootstrap/usr

mkdir /bootstrap/usr/local

mkdir /bootstrap/usr/local/bin

完毕后，执行命令 bash bfinject -P AVPlayer.app -L test

tree-flys-iPhone-7:~/bfinject root# bash bfinject -P AVPlayer.app -L test

[+] Electra detected.

bfinject: md5:commandnot found

bfinject: md5:commandnot found

[+] Injecting into'/var/containers/Bundle/Application/B36F534E-DF04-4BBF-987B-EED3E4B3A6AC/AVPlayer.app/AVPlayer'

[+] Getting Team ID from target application...

[+] Thinning dylib into non-fat arm64 image

[+] Signing injectable .dylib with Team ID DR9UPY28XM and platform entitlements...

jtool /bootstrap/usr/local/bin/ signing error. barfing.

分析 md5: command not found 原因

报错的代码行：

# Use random filenames to avoid cached binaries causing "Killed: 9" messages.

RAND=`ddif=/dev/random bs=1 count=16 2>/dev/null | md5`

RANDOM_NAME="${INJECTOR%/*}/`dd if=/dev/random bs=1 count=16 2>/dev/null | md5`"

看上去 md5 文件缺失，这个比较好解决

tree-flys-iPhone-7:~/bfinject root# md5

bash: md5:commandnot found

方法比较多，编译一个 md5 即可；或者采纳 openssl，如openssl md5, 或者使用 GNU 工具命令如md5sum, 注意处理下前缀或后缀。

tree-flys-iPhone-7:~/bfinject root# echo 'itreefly.com' | md5sum

a24c26e8ba09235dab371b04e5b58936  -

tree-flys-iPhone-7:~/bfinject root# echo 'itreefly.com' | md5sum | sed 's/ .*//'

a24c26e8ba09235dab371b04e5b58936

tree-flys-iPhone-7:~/bfinject root# echo 'itreefly.com' | openssl md5

(stdin)= a24c26e8ba09235dab371b04e5b58936

tree-flys-iPhone-7:~/bfinject root# echo 'itreefly.com' | openssl md5 | sed 's/.* //'

a24c26e8ba09235dab371b04e5b58936

FIX 2

尝试使用md5sum替代md5, 修正下代码：

#RAND=`dd if=/dev/random bs=1 count=16 2>/dev/null | md5`

RAND=`ddif=/dev/random bs=1 count=16 2>/dev/null | md5sum | sed's/ .*//'`

#RANDOM_NAME="${INJECTOR%/*}/`dd if=/dev/random bs=1 count=16 2>/dev/null | md5`"

RANDOM_NAME="${INJECTOR%/*}/`dd if=/dev/random bs=1 count=16 2>/dev/null | md5sum | sed 's/ .*//'`"

# Debug info

echo"*** RAND =$RAND"

echo"*** RANDOM_NAME =$RANDOM_NAME"

测试注入功能

tree-flys-iPhone-7:~/bfinject root# bash bfinject -P AVPlayer.app -L test

[+] Electra detected.

*** RAND = 1c9cf2572f0064d69005b0e4bd2ae5a2

*** RANDOM_NAME = /bootstrap/usr/local/bin/91432177bcba40fb1d026bcf83203e13

[+] Injecting into'/var/containers/Bundle/Application/B36F534E-DF04-4BBF-987B-EED3E4B3A6AC/AVPlayer.app/AVPlayer'

[+] Getting Team ID from target application...

[+] Thinning dylib into non-fat arm64 image

[+] Signing injectable .dylib with Team ID DR9UPY28XM and platform entitlements...

[bfinject4realz] Calling task_for_pid()forPID 2627.

[bfinject4realz] Calling thread_create() on PID 2627

[bfinject4realz] LookingforROP gadget... found at 0x1849b7118

[bfinject4realz] Fake stack frame at 0x108998000

[bfinject4realz] Calling _pthread_set_self() at 0x184c8471c...

[bfinject4realz] Returned from'_pthread_set_self'

[bfinject4realz] Calling dlopen() at 0x1849b6e7c...

[bfinject4realz] Returned from'dlopen'

[bfinject4realz] Success! Library was loaded at 0x1c0167bc0

[+] So long and thanksforall the fish.

再测试脱壳功能，一切 OK👌