目录:
一、APP加固背景
二、APP加固前世今生
三、整体框架
四、详细流程分析
五、总结一、APP加固背景
1.1、概述
Android系统是基于Linux开发己具有其开放性、自由性的一种操作系统，现主要应用于移动设备，如手机、平板电脑和车载系统等。从2007年Google推出第一代Android操作系统至今已有10多年的时间，移动行业的市场份额与规模也在急速增长，现在几乎每人都在用或曾用过接触过Android智能手机。
1.2、安全问题
移动APP越来越普及，大多业务己放到APP中完 成，带来的安全隐患也越来越突出，漏洞、APP破解、恶意代码植入、广告植入、病毒木马、支付篡改、数据爬取等安全问题。
在发版前可通过对APP进行安全检测，加固APP可以提高安全性，解决大部分风险。
二、APP加固前世今生
2.1、APP加固发展与现状
App加固技术，前后经历了四代技术变更，保护级别在每一代都有所提升，破解成本也越来超高，发展流程大致如图2-1所示:
图2-1
第一代加固技术(动态加载):
第一代Android加固技术用于保护应用的逻辑不被逆向与分析，最早普遍在恶意软件中使用，其主要基于虚拟机提供的动态加载技术。
缺陷:只能对抗静态分析，无法对抗攻击者通过动态调试或自定义虚拟机进行脱壳。
第二代加固技术(内存加载):
第二代加固技术在APK修改方面已经完善，能做到对开发的零干扰。开发过程中不需要对应用做特殊处理，只需要在最终发布前进行保护即可。而为了实现这个零干扰的流程，Loader需要处理好Android的组件的生命周期。hook读写等方法，读写文件时进行加解密。
缺陷:只能对抗静态分析，无法对抗攻击者通过动态调试、内存dump或自定义虚拟机进行脱壳。
第三代加固技术(指令抽取):
第三代加固技术对Dex中代码的方法名和方法体进行分离，并对分离的方法体进行加密，通过Hook虚拟机方法，在程序运行的同时对方法进行解密运行。这种保护技术有效的防止了破解者通过内存dump的方式获取明文dex，将保护级别降到了函数级别。
缺陷:无法对抗攻击者通过自定义Android虚拟机进行脱壳。
第四代加固技术(java2C/VMP):
第四代加固技术对DEX中方法提取并转化成native方法后在底层进行注册，在调用native方法的同时在底层使用自定义解释器解释虚拟机指令。
java2c是将DEX文件内的函数被标记为native，内容被抽离并转换成一个符合JNI要求的动态库。动态库内通过JNI方法和Android系统进行交互。
缺陷：不论VMP还是java2c，都必须通过虚拟机提供的JNI接口与虚拟机进行交互，攻击者可以直接hook系统JNI接口、记录和分析执行流程，进而推断出完整DEX程序。
2.1、产品介绍
梆梆加固产品主要分为免费版与定制版，应用场景如下：
防逆向（Anti-RE） :
抽取classes.dex中的所有代码，剥离敏感函数功能，混淆关键逻辑代码，整体文件深度加密加壳，防止通过apktool，dex2jar，JEB等静态工具来查看应用的Java层代码，防止通过IDA，readelf等工具对so里面的逻辑进行分析，保护native代码。
防篡改（Anti-tamper）
每个代码文件、资源文件、配置文件都会分配唯一识别指纹，替换任何一个文件，将会导致应用无法运行，存档替换、病毒广告植入、内购破解、功能屏蔽等恶意行为将无法实施。
防调试（Anti-debug）
多重加密技术防止代码注入，彻底屏蔽游戏外挂、应用辅助工具，避免钓鱼攻击、交易劫持、数据修改等调试行为。
防窃取（Storage Encryption）
支持存储数据加密，提供输入键盘保护、通讯协议加密、内存数据变换、异常进程动态跟踪等安防技术，有效防止针对应用动、静态数据的捕获、劫持和篡改。免费版与定制版本区别如图2-2所示：
图2-2
免费版本相对于定制化加固在安全能力方面要弱很多，我们分析的目标是定制版本的加固。
三、整体框架
梆梆定制版加固保护代码的方式主要分为两种，一是指令抽取，二是指令虚拟化，指令还原与虚拟化基本的流程与逻辑如图3-1所示：
图3-1
四、详细流程分析
4.1 加固后APP基本情况介绍
通过JEB反编译DUMP出来的DEX，方法指令抽取与指令虚拟化后如图4-1与4-2所示，方法指令抽取后的结果如图4-1所示：
图4-1
方法指令虚拟化后大部分函数是调用JniLib.cV解析执行的，最后一个参数是一个函数code索引，用来查找被虚拟化后的指令，其它是方法参数，如图4-2所示：
图4-2
4.2 So壳简单分析
壳的SO文件本身做了加壳保护，壳入口为.init_proc，如图4-3所示：
图4-3
解壳流程如大致为获取加密的代码基址->解密->修改属性，解密代码如下：
#define CODE_DATA_SIZE 0X00053DB3#define CODE_DATA_OFFSET 0XE500int DecCode(int copydata, unsigned int datasize, int codebufer, int* a4){index_2 = 0;v5 = 1;index = 0;v7 = 0;while (1){while (1){v8 = (v7 & 0x7F) == 0;if ((v7 & 0x7F) != 0)v7 *= 2;elsev7 = *(unsigned __int8*)(copydata + index);if (v8){v7 = 2 * v7 + 1;++index;}if ((v7 & 0x100) == 0)break;codebyte = *(unsigned char*)(copydata + index++);*(unsigned char*)(codebufer + index_2++) = codebyte;}for (i = 1; ; i = v20 + ((unsigned int)(v7 << 23) >> 31)){v11 = (v7 & 0x7F) == 0;if ((v7 & 0x7F) != 0)v12 = 2 * v7;elsev12 = *(unsigned __int8*)(copydata + index);if (v11){v12 = 2 * v12 + 1;++index;}v13 = (v12 & 0x7F) == 0;v14 = v12 << 23;if ((v12 & 0x7F) != 0)v15 = 2 * v12;elsev15 = *(unsigned __int8*)(copydata + index);if (v13)v15 = 2 * v15 + 1;v16 = 2 * i;if (v13)++index;v17 = v16 + (v14 >> 31);if ((v15 & 0x100) != 0)break;v18 = (v15 & 0x7F) == 0;if ((v15 & 0x7F) == 0)v15 = *(unsigned __int8*)(copydata + index);v19 = v17 + 0x7FFFFFFF;v7 = 2 * v15;if (v18)++v7;v20 = 2 * v19;if (v18)++index;}index_1 = index;if (v17 != 2)break;v22 = (v15 & 0x7F) == 0;if ((v15 & 0x7F) != 0)v15 *= 2;elsev15 = *(unsigned __int8*)(copydata + index);if (v22)v15 = 2 * v15 + 1;if (v22)++index;v23 = (v15 >> 8) & 1;LABEL_41:v25 = (v15 & 0x7F) == 0;if ((v15 & 0x7F) != 0)v7 = 2 * v15;elsev7 = *(unsigned __int8*)(copydata + index);if (v25)v7 = 2 * v7 + 1;v26 = 2 * v23;if (v25)++index;v27 = v26 + ((unsigned int)(v7 << 23) >> 31);if (!v27){v28 = 1;do{v29 = (v7 & 0x7F) == 0;if ((v7 & 0x7F) != 0)v30 = 2 * v7;elsev30 = *(unsigned __int8*)(copydata + index);if (v29){v30 = 2 * v30 + 1;++index;}v31 = (v30 & 0x7F) == 0;v32 = v30 << 23;if ((v30 & 0x7F) != 0)v7 = 2 * v30;elsev7 = *(unsigned __int8*)(copydata + index);if (v31)v7 = 2 * v7 + 1;v33 = 2 * v28;if (v31)++index;v28 = v33 + (v32 >> 31);} while ((v7 & 0x100) == 0);v27 = v28 + 2;}if (v5 > 0x500)v34 = v27 + 1;elsev34 = v27;v35 = (unsigned char*)(codebufer + index_2 - v5);*(unsigned char*)(codebufer + index_2) = *v35;v36 = index_2 + 1;v37 = &v35[v34];v38 = codebufer + index_2;do{v39 = *++v35;*(unsigned char*)++v38 = v39;} while (v35 != v37);index_2 = v36 + v34;}v24 = *(unsigned __int8*)(copydata + index++) + ((v17 + 16777213) << 8);if (v24 != -1){v23 = !(*(unsigned char*)(copydata + index_1) & 1);v5 = (v24 >> 1) + 1;goto LABEL_41;}*a4 = index_2;if (index == datasize)return 0;if (index >= datasize)return -201;return -205;}int __fastcall sub_D1F2EA88(int result, int a2){int v2; // r4unsigned int v3; // r12int v4; // r6int v5; // r7int v6; // r5int v7; // r2unsigned int v8; // r5int v9; // r3int v10; // r6unsigned int v11; // r1v2 = *(int*)(result + a2 + 8);v3 = *(int*)(result + a2 + 12);v4 = *(int*)(result + a2 + 16);v5 = *(int*)(result + a2 + 20);v6 = *(int*)(result + a2 + 24);if (*(int*)(result + a2) == 2146926590){result += *(int*)(result + a2 + 4);v7 = 0;v8 = v3 + 4 * v6;v9 = 0;v10 = v5 + v4;while (v9 != v2){v11 = *(int*)(result + 8 * v9);if (v11 >= v3 && v11 < v8)* (int*)(result + 8 * v9) = v10 + 4 * v7++;++v9;}}return result;}
4.3 DEX 指令抽取原理分析
JNI_OnLoad 分析
壳解密完成后执行到JNI_OnLoad方法，JNI_OnLoad主要完成几个重要步骤。
1、注册JNI方法，方法如下：
i()Vattach(Landroid/app/Application;Landroid/content/Context;)Vb(Landroid/content/Context;Landroid/app/Application;)Vc()Vd(Ljava/lang/String;)Ljava/lang/String;e(Ljava/lang/Object;Ljava/util/List;Ljava/lang/String;)[Ljava/lang/Object;f()[Ljava/lang/String;g()[Ljava/lang/String;h()[Ljava/lang/String;n()[Ljava/lang/String;j()[Ljava/lang/String;k()Ljava/lang/String;l()Ljava/lang/String;m()Ljava/lang/String;
2、hook libc.so方法，hook如下方法：
__open__openatwritereadmunmapmsync__mmap2pread64ftruncate64close
3、读取classes0.jar、classes.dgc并解密，代码逻辑如下：
//读取资源文件seg131:CEE8E1B0 01 1C MOVS R1, R0seg131:CEE8E1B2 06 98 LDR R0, [SP,#0x18]seg131:CEE8E1B4 D1 F7 A4 EA BLX AAssetManager_fromJava_0seg131:CEE8E1B8 31 1C MOVS R1, R6seg131:CEE8E1BA 03 22 MOVS R2, #3seg131:CEE8E1BC D1 F7 A6 EA BLX AAssetManager_open_0seg131:CEE8E1C0 17 90 STR R0, [SP,#0x5C]seg131:CEE8E1C2 D1 F7 B0 EA BLX AAsset_getBuffer_0seg131:CEE8E1C6 1D 90 STR R0, [SP,#0x74]seg131:CEE8E1C8 ; START OF FUNCTION CHUNK FOR map_buferseg131:CEE8E1C8seg131:CEE8E1C8 loc_CEE8E1C8 ; CODE XREF: map_bufer+62↑jseg131:CEE8E1C8 17 98 LDR R0, [SP,#0x5C] ; assetseg131:CEE8E1CA D1 F7 A6 EA BLX AAsset_getLength_0seg131:CEE8E1CE 00 23 MOVS R3, #0seg131:CEE8E1D0 33 93 STR R3, [SP,#0xCC]seg131:CEE8E1D2 33 9A LDR R2, [SP,#0xCC]seg131:CEE8E1D4 A4 4A LDR R2, =0xFFFFFC84//解密代码seg131:CEE72568 EXPORT Dec_classes_dgc_p1053869DF5E0CBA2E958A4809845A982seg131:CEE72568 Dec_classes_dgc_p1053869DF5E0CBA2E958A4809845A982seg131:CEE72568 var_248= -0x248seg131:CEE72568 var_244= -0x244seg131:CEE72568 var_240= -0x240seg131:CEE72568 var_238= -0x238seg131:CEE72568 var_11C= -0x11Cseg131:CEE72568 var_1C= -0x1Cseg131:CEE72568 arg_48= 0x48seg131:CEE72568 arg_314= 0x314seg131:CEE72568 F0 B5 PUSH {R4-R7,LR}seg131:CEE7256A 87 4C LDR R4, loc_CEE72788seg131:CEE7256C 87 4A LDR R2, loc_CEE7278Cseg131:CEE7256E 88 4B LDR R3, loc_CEE72790seg131:CEE72570 A5 44 ADD SP, R4seg131:CEE72572 01 90 STR R0, [SP,#0x248+var_244]seg131:CEE72574 80 20 MOVS R0, #0x80seg131:CEE72576 7A 44 ADD R2, PCseg131:CEE72578 D6 58 LDR R6, [R2,R3]seg131:CEE7257A 00 91 STR R1, [SP,#0x248+var_248]seg131:CEE7257Cseg131:CEE7257C loc_CEE7257Cseg131:CEE7257C 80 02 LSLS R0, R0, #0xAseg131:CEE7257E 33 68 LDR R3, [R6]seg131:CEE72580 04 96 STR R6, [SP,#0x248+var_238]seg131:CEE72582 8B 93 STR R3, [SP,#0x248+var_1C]seg131:CEE72584 81 42 CMP R1, R0seg131:CEE72586 00 DD BLE loc_CEE7258Aseg131:CEE72588 00 90 STR R0, [SP,#0x248+var_248]seg131:CEE7258Aseg131:CEE7258A loc_CEE7258Aseg131:CEE7258A 82 4B LDR R3, loc_CEE72794seg131:CEE7258C 7B 44 ADD R3, PCseg131:CEE7258E 1B 68 LDR R3, [R3]seg131:CEE72590 00 2B CMP R3, #0seg131:CEE72592 40 D1 BNE loc_CEE72616seg131:CEE72594 80 49 LDR R1, loc_CEE72798seg131:CEE72596 52 58 LDR R2, [R2,R1]seg131:CEE72598 12 68 LDR R2, [R2]seg131:CEE7259A 02 92 STR R2, [SP,#0x248+var_240]seg131:CEE7259C 80 22 52 00 MOVS R2, #0x100seg131:CEE725A0seg131:CEE725A0 loc_CEE725A0seg131:CEE725A0 4B A9 ADD R1, SP, #0x248+var_11Cseg131:CEE725A2 5B 54 STRB R3, [R3,R1]seg131:CEE725A4seg131:CEE725A4 loc_CEE725A4seg131:CEE725A4 01 33 ADDS R3, #1seg131:CEE725A6 93 42 CMP R3, R2seg131:CEE725A8 FA D1 BNE loc_CEE725A0seg131:CEE725AA 00 23 MOVS R3, #0seg131:CEE725AC 0F 27 MOVS R7, #0xFseg131:CEE725AE 1D 1C MOVS R5, R3seg131:CEE725B0 18 1C MOVS R0, R3seg131:CEE725B2 9C 46 MOV R12, R3seg131:CEE725B4seg131:CEE725B4 loc_CEE725B4seg131:CEE725B4 02 9A LDR R2, [SP,#(dword_CEE727D4 - 0xCEE727CC)]seg131:CEE725B6 46 5C LDRB R6, [R0,R1]seg131:CEE725B8seg131:CEE725B8 loc_CEE725B8seg131:CEE725B8 64 46 MOV R4, R12seg131:CEE725BA D2 5C LDRB R2, [R2,R3]seg131:CEE725BC 01 33 ADDS R3, #1seg131:CEE725BE 92 19 ADDS R2, R2, R6seg131:CEE725C0 55 19 ADDS R5, R2, R5seg131:CEE725C2 FF 22 MOVS R2, #0xFFseg131:CEE725C4 15 40 ANDS R5, R2seg131:CEE725C6 DA 0F LSRS R2, R3, #0x1Fseg131:CEE725C8seg131:CEE725C8 loc_CEE725C8seg131:CEE725C8 9F 42 CMP R7, R3seg131:CEE725CAseg131:CEE725CA loc_CEE725CAseg131:CEE725CA 62 41 ADCS R2, R4seg131:CEE725CC 52 42 NEGS R2, R2seg131:CEE725CE 13 40 ANDS R3, R2seg131:CEE725D0seg131:CEE725D0 loc_CEE725D0seg131:CEE725D0 4A 5D LDRB R2, [R1,R5]seg131:CEE725D2 0A 54 STRB R2, [R1,R0]seg131:CEE725D4 80 22 MOVS R2, #0x80seg131:CEE725D6 01 30 ADDS R0, #1seg131:CEE725D8 4E 55 STRB R6, [R1,R5]seg131:CEE725DA 52 00 LSLS R2, R2, #1seg131:CEE725DC 90 42 CMP R0, R2seg131:CEE725DE E9 D1 BNE loc_CEE725B4seg131:CEE725DEseg131:CEE725DEseg131:CEE725E0seg131:CEE725E0seg131:CEE725E0 loc_CEE725E0seg131:CEE725E0 00 22 MOVS R2, #0seg131:CEE725E2 FF 27 MOVS R7, #0xFFseg131:CEE725E4 10 1C MOVS R0, R2seg131:CEE725E6 01 99 LDR R1, [SP,#4]seg131:CEE725E8 00 9B LDR R3, [SP]seg131:CEE725EA CC 18 ADDS R4, R1, R3seg131:CEE725EC ; START OF FUNCTION CHUNK FOR DecString_5seg131:CEE725ECseg131:CEE725EC loc_CEE725ECseg131:CEE725ECseg131:CEE725EC A1 42 CMP R1, R4seg131:CEE725EE 00 D1 BNE loc_CEE725F2seg131:CEE725F0 BE E0 B loc_CEE72770seg131:CEE725F2seg131:CEE725F2 loc_CEE725F2seg131:CEE725F2 01 30 ADDS R0, #1seg131:CEE725F4seg131:CEE725F4 loc_CEE725F4seg131:CEE725F4 4B AE ADD R6, SP, #0x248+var_11Cseg131:CEE725F6 38 40 ANDS R0, R7seg131:CEE725F8 33 5C LDRB R3, [R6,R0]seg131:CEE725FAseg131:CEE725FA loc_CEE725FAseg131:CEE725FA D2 18 ADDS R2, R2, R3seg131:CEE725FC 3A 40 ANDS R2, R7seg131:CEE725FE B5 5C LDRB R5, [R6,R2]seg131:CEE72600 35 54 STRB R5, [R6,R0]seg131:CEE72602 B3 54 STRB R3, [R6,R2]seg131:CEE72604 35 5C LDRB R5, [R6,R0]seg131:CEE72606 ED 18 ADDS R5, R5, R3seg131:CEE72608 3D 40 ANDS R5, R7seg131:CEE7260A 0B 78 LDRB R3, [R1]seg131:CEE7260C 75 5D LDRB R5, [R6,R5]seg131:CEE7260E 6B 40 EORS R3, R5seg131:CEE72610 0B 70 STRB R3, [R1]seg131:CEE72612 01 31 ADDS R1, #1seg131:CEE72614 EA E7 B loc_CEE725ECseg131:CEE72616seg131:CEE72616 loc_CEE72616seg131:CEE72616 01 2B CMP R3, #1seg131:CEE72618 00 D0 BEQ loc_CEE7261Cseg131:CEE7261Aseg131:CEE7261A loc_CEE7261Aseg131:CEE7261A A9 E0 B loc_CEE72770seg131:CEE7261Cseg131:CEE7261C loc_CEE7261Cseg131:CEE7261C 5E 4B LDR R3, loc_CEE72798seg131:CEE7261E 06 A8 ADD R0, SP, #0x248+var_230seg131:CEE72620 D3 58 LDR R3, [R2,R3]seg131:CEE72620 ; END OF FUNCTION CHUNK FOR DecString_5seg131:CEE72622 19 68 LDR R1, [R3]seg131:CEE72624 FF F7 48 FC BL _Z33p70A9D4C5060D53A50764B3505C16E6F2P33p4ABCBA1E0CA9993D681F7E561B3486DCPhseg131:CEE72628 00 98 LDR R0, [SP]seg131:CEE7262A EC F7 98 EF BLX malloc_0seg131:CEE7262E 01 99 LDR R1, [SP,#4]seg131:CEE72630 00 9A LDR R2, [SP]seg131:CEE72632 06 1C MOVS R6, R0seg131:CEE72634 EC F7 80 EF BLX memcpy_0_seg131:CEE72638 01 9D LDR R5, [SP,#4]seg131:CEE7263A loc_CEE7263Aseg131:CEE7263A 00 9B LDR R3, [SP,#0x130+var_130]seg131:CEE7263Cseg131:CEE7263C loc_CEE7263Cseg131:CEE7263C 01 9A LDR R2, [SP,#0x130+var_12C]seg131:CEE7263E 5B 1B SUBS R3, R3, R5seg131:CEE72640 D3 18 ADDS R3, R2, R3seg131:CEE72642 00 2B CMP R3, #(unk_13F0E000 - 0x13F0E000)seg131:CEE72644seg131:CEE72644 loc_CEE72644seg131:CEE72644 00 DC BGT loc_CEE72648seg131:CEE72646 93 E0 B loc_CEE72770seg131:CEE72648 loc_CEE72648seg131:CEE72648 27 AF ADD R7, SP, #0x130+var_94seg131:CEE7264A 00 21 MOVS R1, #0 ; intseg131:CEE7264C 90 22 MOVS R2, #0x90 ; size_tseg131:CEE7264E 38 1C MOVS R0, R7 ; void *seg131:CEE72650 EC F7 96 EF BLX memset_0seg131:CEE72654 31 78 LDRB R1, [R6]seg131:CEE72656 73 78 LDRB R3, [R6,#1]seg131:CEE72658 B2 78 LDRB R2, [R6,#2]seg131:CEE7265A 09 06 LSLS R1, R1, #0x18seg131:CEE7265C 1B 04 LSLS R3, R3, #0x10seg131:CEE7265E 0B 43 ORRS R3, R1seg131:CEE72660 F1 78 LDRB R1, [R6,#3]seg131:CEE72662 12 02 LSLS R2, R2, #arg_8seg131:CEE72664 02 97 STR R7, [SP,#0x130+var_128]seg131:CEE72666 0B 43 ORRS R3, R1seg131:CEE72668 13 43 ORRS R3, R2seg131:CEE7266A 27 93 STR R3, [SP,#0x130+var_94]seg131:CEE7266C 31 79 LDRB R1, [R6,#4]seg131:CEE7266E 73 79 LDRB R3, [R6,#5]seg131:CEE72670 B2 79 LDRB R2, [R6,#arg_4+2]seg131:CEE72672 09 06 LSLS R1, R1, #0x18seg131:CEE72674 1B 04 LSLS R3, R3, #0x10seg131:CEE72676 0B 43 ORRS R3, R1seg131:CEE72678 F1 79 LDRB R1, [R6,#7]seg131:CEE7267Aseg131:CEE7267A 12 02 LSLS R2, R2, #8seg131:CEE7267C 0B 43 ORRS R3, R1seg131:CEE7267Eseg131:CEE7267E loc_CEE7267Eseg131:CEE7267E 13 43 ORRS R3, R2seg131:CEE72680seg131:CEE72680 loc_CEE72680seg131:CEE72680 7B 60 STR R3, [R7,#4]seg131:CEE72682 31 7A LDRB R1, [R6,#8]seg131:CEE72684 73 7A LDRB R3, [R6,#9]seg131:CEE72686 B2 7A LDRB R2, [R6,#arg_8+2]seg131:CEE72688 09 06 LSLS R1, R1, #0x18seg131:CEE7268A 1B 04 LSLS R3, R3, #0x10seg131:CEE7268C 0B 43 ORRS R3, R1seg131:CEE7268E F1 7A LDRB R1, [R6,#0xB]seg131:CEE72690seg131:CEE72690 loc_CEE72690seg131:CEE72690 12 02 LSLS R2, R2, #8seg131:CEE72692 0B 43 ORRS R3, R1seg131:CEE72694 13 43 ORRS R3, R2seg131:CEE72696 BB 60 STR R3, [R7,#8]seg131:CEE72698 31 7B LDRB R1, [R6,#0xC]seg131:CEE7269A 73 7B LDRB R3, [R6,#0xD]seg131:CEE7269C B2 7B LDRB R2, [R6,#0xE]seg131:CEE7269E 09 06 LSLS R1, R1, #0x18seg131:CEE726A0 loc_CEE726A0seg131:CEE726A0 1B 04 LSLS R3, R3, #0x10seg131:CEE726A2 0B 43 ORRS R3, R1seg131:CEE726A4 F1 7B LDRB R1, [R6,#0xF]seg131:CEE726A6 12 02 LSLS R2, R2, #8seg131:CEE726A8 0B 43 ORRS R3, R1seg131:CEE726AA 13 43 ORRS R3, R2seg131:CEE726ACseg131:CEE726AC loc_CEE726ACseg131:CEE726AC FB 60 STR R3, [R7,#0xC]seg131:CEE726AEseg131:CEE726AEseg131:CEE726AE loc_CEE726AEseg131:CEE726AE 06 AB ADD R3, SP, #0x18seg131:CEE726B0 05 93 STR R3, [SP,#0x14]seg131:CEE726B2 3A 4B LDR R3, loc_CEE7279Cseg131:CEE726B4 00 21 MOVS R1, #0seg131:CEE726B6seg131:CEE726B6 loc_CEE726B6seg131:CEE726B6 7B 44 ADD R3, PCseg131:CEE726B8 9C 46 MOV R12, R3seg131:CEE726BA loc_CEE726BAseg131:CEE726BA 60 46 MOV R0, R12seg131:CEE726BC 02 9B LDR R3, [SP,#8]seg131:CEE726BE 64 46 MOV R4, R12seg131:CEE726C0 loc_CEE726C0seg131:CEE726C0 5F 18 ADDS R7, R3, R1seg131:CEE726C2 7B 68 LDR R3, [R7,#4]seg131:CEE726C4 BA 68 LDR R2, [R7,#8]seg131:CEE726C6 5A 40 EORS R2, R3seg131:CEE726C8 FB 68 LDR R3, [R7,#0xC]seg131:CEE726CA 5A 40 EORS R2, R3seg131:CEE726CC loc_CEE726CCseg131:CEE726CC 05 9B LDR R3, [SP,#0x14]seg131:CEE726CEseg131:CEE726CE loc_CEE726CEseg131:CEE726CE 5B 18 ADDS R3, R3, R1seg131:CEE726D0 5B 68 LDR R3, [R3,#4]seg131:CEE726D2 loc_CEE726D2seg131:CEE726D2 5A 40 EORS R2, R3seg131:CEE726D4 13 0E LSRS R3, R2, #0x18seg131:CEE726D6 C3 5C LDRB R3, [R0,R3]seg131:CEE726D8 loc_CEE726D8seg131:CEE726D8 FF 20 MOVS R0, #0xFFseg131:CEE726DA 10 40 ANDS R0, R2seg131:CEE726DC 20 5C LDRB R0, [R4,R0]seg131:CEE726DE FF 24 MOVS R4, #0xFFseg131:CEE726E0seg131:CEE726E0 loc_CEE726E0seg131:CEE726E0 1B 06 LSLS R3, R3, #0x18seg131:CEE726E2 03 43 ORRS R3, R0seg131:CEE726E4seg131:CEE726E4 loc_CEE726E4seg131:CEE726E4 10 0C LSRS R0, R2, #0x10seg131:CEE726E6 20 40 ANDS R0, R4seg131:CEE726E8 64 46 MOV R4, R12seg131:CEE726EA 20 5C LDRB R0, [R4,R0]seg131:CEE726EC 12 0A LSRS R2, R2, #8seg131:CEE726EE 00 04 LSLS R0, R0, #0x10seg131:CEE726F0seg131:CEE726F0 loc_CEE726F0seg131:CEE726F0 18 43 ORRS R0, R3seg131:CEE726F2 FF 23 MOVS R3, #0xFFseg131:CEE726F4 loc_CEE726F4seg131:CEE726F4 1A 40 ANDS R2, R3seg131:CEE726F6 A3 5C LDRB R3, [R4,R2]seg131:CEE726F8 02 9A LDR R2, [SP,#8]seg131:CEE726FA 1B 02 LSLS R3, R3, #8seg131:CEE726FC 03 43 ORRS R3, R0seg131:CEE726FE 1C 1C MOVS R4, R3seg131:CEE72700 1E 20 MOVS R0, #0x1Eseg131:CEE72702 C4 41 RORS R4, R0seg131:CEE72704 8A 58 LDR R2, [R1,R2]seg131:CEE72706 16 20 MOVS R0, #(loc_CEE72932 - 0xCEE7291C)seg131:CEE72708 03 92 STR R2, [SP,#0xC]seg131:CEE7270A 5A 40 EORS R2, R3seg131:CEE7270Cseg131:CEE7270C loc_CEE7270Cseg131:CEE7270C 62 40 EORS R2, R4seg131:CEE7270E 1C 1C MOVS R4, R3seg131:CEE72710 C4 41 RORS R4, R0seg131:CEE72712 0E 20 MOVS R0, #0xEseg131:CEE72714seg131:CEE72714 loc_CEE72714seg131:CEE72714 62 40 EORS R2, R4seg131:CEE72716 1C 1C ADDS R4, R3, #0seg131:CEE72718 loc_CEE72718seg131:CEE72718 C4 41 RORS R4, R0seg131:CEE7271A 08 20 MOVS R0, #8seg131:CEE7271C C3 41 RORS R3, R0seg131:CEE7271E 62 40 EORS R2, R4seg131:CEE72720 5A 40 EORS R2, R3seg131:CEE72722 04 31 ADDS R1, #4seg131:CEE72724 3A 61 STR R2, [R7,#0x10]seg131:CEE72726seg131:CEE72726 loc_CEE72726seg131:CEE72726 80 29 CMP R1, #0x80seg131:CEE72728seg131:CEE72728 loc_CEE72728seg131:CEE72728 C7 D1 BNE loc_CEE726BAseg131:CEE7272A 4A 9B LDR R3, [SP,#0x128]seg131:CEE7272C 10 36 ADDS R6, #0x10seg131:CEE7272E 1A 0E LSRS R2, R3, #0x18seg131:CEE72730seg131:CEE72730 loc_CEE72730seg131:CEE72730 2A 70 STRB R2, [R5]seg131:CEE72732 1A 0C LSRS R2, R3, #0x10seg131:CEE72734 6A 70 STRB R2, [R5,#1]seg131:CEE72736 EB 70 STRB R3, [R5,#3]seg131:CEE72738 1A 0A LSRS R2, R3, #8seg131:CEE7273A 49 9B LDR R3, [SP,#0x124]seg131:CEE7273C AA 70 STRB R2, [R5,#2]seg131:CEE7273E 1A 0E LSRS R2, R3, #0x18seg131:CEE72740 2A 71 STRB R2, [R5,#4]seg131:CEE72742 1A 0C LSRS R2, R3, #0x10seg131:CEE72744seg131:CEE72744 loc_CEE72744seg131:CEE72744 6A 71 STRB R2, [R5,#5]seg131:CEE72746 EB 71 STRB R3, [R5,#7]seg131:CEE72748seg131:CEE72748 loc_CEE72748seg131:CEE72748 1A 0A LSRS R2, R3, #8seg131:CEE7274A 48 9B LDR R3, [SP,#0x120]seg131:CEE7274C AA 71 STRB R2, [R5,#arg_4+2]seg131:CEE7274E 1A 0E LSRS R2, R3, #0x18seg131:CEE72750seg131:CEE72750 loc_CEE72750seg131:CEE72750 2A 72 STRB R2, [R5,#8]seg131:CEE72752 1A 0C LSRS R2, R3, #0x10seg131:CEE72754 6A 72 STRB R2, [R5,#9]seg131:CEE72756 EB 72 STRB R3, [R5,#0xB]seg131:CEE72758 1A 0A LSRS R2, R3, #8seg131:CEE7275A 47 9B LDR R3, [SP,#0x11C]seg131:CEE7275C AA 72 STRB R2, [R5,#arg_8+2]seg131:CEE7275E 1A 0E LSRS R2, R3, #0x18seg131:CEE72760 2A 73 STRB R2, [R5,#0xC]seg131:CEE72762 1A 0C LSRS R2, R3, #0x10seg131:CEE72764 loc_CEE72764seg131:CEE72764 6A 73 STRB R2, [R5,#0xD]seg131:CEE72766 1A 0A LSRS R2, R3, #8seg131:CEE72768 AA 73 STRB R2, [R5,#0xE]seg131:CEE7276A EB 73 STRB R3, [R5,#0xF]seg131:CEE7276C 10 35 ADDS R5, #0x10seg131:CEE7276E 64 E7 B loc_CEE7263Aseg131:CEE72770seg131:CEE72770 loc_CEE72770seg131:CEE72770 04 9B LDR R3, [SP,#0x248+var_238]seg131:CEE72772 8B 9A LDR R2, [SP,#0x248+var_1C]seg131:CEE72774 1B 68 LDR R3, [R3]seg131:CEE72776 9A 42 CMP R2, R3seg131:CEE72778 01 D0 BEQ loc_CEE7277Eseg131:CEE7277A EC F7 D8 EE BLX sub_CEE5F52Cseg131:CEE7277Eseg131:CEE7277E loc_CEE7277Eseg131:CEE7277E 8D 23 MOVS R3, #0x8Dseg131:CEE72780seg131:CEE72780 loc_CEE72780seg131:CEE72780 9B 00 LSLS R3, R3, #2seg131:CEE72782 9D 44 ADD SP, R3seg131:CEE72784 F0 BD POP {R4-R7,PC}
classes0.jar:解密出DEX明文。
classes.dgc:解密出被抽取的指令。
4、hook libart.so虚拟机方法
我调试的系统版为android 9，该系统主要hook了如下两个方法：
art::ArtDexFileLoader::Openart::ClassLinker::LoadMethod
5、反调试
反调试主要分为以下几种方式：
1、fork多进程相互监控。
2、多线程监控，创建3个线程监控调试状态，检查TracerPid和命令行中的gdb gdbserver android_server，文件监控。
3、hook ptrace 方法判断是否有调试器。
4、hook art::Runtime::AttachAgent 监控是否在调试
5、hook vmDebug_notifyDebuggerActivityStart监控调试器
方法指令还原：
当被抽取指令的方法被执行时，会调用art::ClassLinker::LoadMethod，在hook LoadMethod中，先判断是否为目标方法，然后修复，会给每一个加载的目标类方法设置一个DEX文件类方法索引，以及关联一个ArtMethod对象指针数组，如下所示：
//判断是否为目标方法seg157:CEE75928 3A A9 ADD R1, SP, #0xE8seg157:CEE7592A 04 22 MOVS R2, #4seg157:CEE7592C 9B 6A LDR R3, [R3,#0x28]seg157:CEE7592E 62 26 MOVS R6, #0x62 ; 'b'seg157:CEE75930 18 1C MOVS R0, R3seg157:CEE75932 04 93 STR R3, [SP,#0x10]seg157:CEE75934 E9 F7 CC EE BLX memcmp_0_seg157:CEE75938 00 28 CMP R0, #0 ; 比较是否为目标方法seg157:CEE7593A 00 D1 BNE loc_CEE7593Eseg157:CEE7593C 03 E7 B loc_CEE75746//修复方法索引seg156:CEE75C3C 12 9B LDR R3, [SP,#0x48] ; 进入修复流程seg156:CEE75C3E 3A 98 LDR R0, [SP,#0xE8]seg156:CEE75C40seg156:CEE75C40 loc_CEE75C40seg156:CEE75C40 5C 26 MOVS R6, #0x5C ; '\'seg156:CEE75C42 5B 68 LDR R3, [R3,#4]seg156:CEE75C44seg156:CEE75C44 loc_CEE75C44seg156:CEE75C44 04 93 STR R3, [SP,#0x10]seg156:CEE75C46 12 9B LDR R3, [SP,#0x48]seg156:CEE75C48 04 99 LDR R1, [SP,#0x10]seg156:CEE75C4A DB 68 LDR R3, [R3,#0xC]seg156:CEE75C4C 07 93 STR R3, [SP,#0x1C]seg156:CEE75C4E 1A 1C MOVS R2, R3seg156:CEE75C50 12 9B LDR R3, [SP,#0x48]seg156:CEE75C5seg156:CEE75C52 08 33 ADDS R3, #8seg156:CEE75C54seg156:CEE75C54 loc_CEE75C54seg156:CEE75C54 FC F7 86 FB BL fixcode_p9AB5A5CE7069322A1CDE6359EAB11FAEseg156:CEE75C58 12 9B LDR R3, [SP,#0x48]seg156:CEE75C5A 9B 68 LDR R3, [R3,#8]seg156:CEE75C5C 1A 93 STR R3, [SP,#0x68]seg156:CEE75C5E 83 4B LDR R3, loc_CEE75E6Cseg156:CEE75C60 FB 58 LDR R3, [R7,R3]seg156:CEE75C62 04 93 STR R3, [SP,#0x10]seg156:CEE75C64 1B 78 LDRB R3, [R3]seg156:CEE75C66 00 2B CMP R3, #0//根据解密后的classes.dgc查找索引修复,循环修复每一个方法seg156:CEE723D4 cmp_endseg156:CEE723D4 B5 42 CMP R5, R6seg156:CEE723D6 00 DB BLT FindTable_dgcseg156:CEE723D8 A8 E0 B loc_CEE7252Cseg156:CEE723DA FindTable_dgcseg156:CEE723DA 13 78 LDRB R3, [R2]seg156:CEE723DC 02 98 LDR R0, [SP,#arg_8]seg156:CEE723DE 05 91 STR R1, [SP,#0x14]seg156:CEE723E0 63 40 EORS R3, R4seg156:CEE723E2 C3 5C LDRB R3, [R0,R3]seg156:CEE723E4 13 70 STRB R3, [R2]seg156:CEE723E6 05 9B LDR R3, [SP,#0x14+arg_0]seg156:CEE723E8 07 23 MOVS R3, #7seg156:CEE723EAseg156:CEE723EA loc_CEE723EAseg156:CEE723EA 06 93 STR R3, [SP,#0x18]seg156:CEE723EC 00 23 MOVS R3, #0seg156:CEE723EEseg156:CEE723EE loc_CEE723EEseg156:CEE723EE 06 98 LDR R0, [SP,#0x18]seg156:CEE723F0seg156:CEE723F0 def_CEE723FAseg156:CEE723F0 0F 28 CMP R0, #0xFseg156:CEE723F2 00 D1 BNE loc_CEE723F6seg156:CEE723F4 9E E0 B index__seg156:CEE723F6seg156:CEE723F6 loc_CEE723F6seg156:CEE723F6 0E 28 CMP R0, #0xEseg156:CEE723F8seg156:CEE723F8 loc_CEE723F8seg156:CEE723F8 FA D8 BHI def_CEE723FA
4.4 DEX VMP原理分析
VMP的实现逻辑是在libdexjni.so中，在java层注册如下几个jni方法供被虚拟化的方法调用：
public static native byte cB(Object[] arg0)public static native char cC(Object[] arg0)public static native double cD(Object[] arg0)public static native float cF(Object[] arg0)public static native int cI(Object[] arg0)public static native long cJ(Object[] arg0)public static native Object cL(Object[] arg0)public static native short cS(Object[] arg0)public static native void cV(Object[] arg0)public static native boolean cZ(Object[] arg0)
如果加载的方法中调用JniLib.cV这样的Native方法时，该方法指令被虚拟化，如图4-4所示：
图4-4
JNI方法中前几个参数为原始方法参数，最后一个整形参数是一个索引值，虚拟机解释执行的过程主要分为如下几个步骤：
1、根据Java层传入的最后一个整形参数索引值获取方法的DexCode指令，代码如下：
seg135:C6299EF0 loc_C6299EF0seg135:C6299EF0 90 47 BLX R2 ; GetArrayLength，获取参数个数seg135:C6299EF2 AD 21 MOVS R1, #0xADseg135:C6299EF4 09 91 STR R1, [SP,#0x24]seg135:C6299EF6 89 00 LSLS R1, R1, #2seg135:C6299EF8 32 68 LDR R2, [R6]seg135:C6299EFA 53 58 LDR R3, [R2,R1]seg135:C6299EFC 44 1E SUBS R4, R0, #1seg135:C6299EFE 30 46 MOV R0, R6seg135:C6299F00 29 46 MOV R1, R5seg135:C6299F02 22 46 MOV R2, R4seg135:C6299F04seg135:C6299F04 loc_C6299F04seg135:C6299F04 98 47 BLX R3 ; GetObjectArrayElement,获取最后一个参数seg135:C6299F06 01 46 MOV R1, R0seg135:C6299F08 9C 48 LDR R0,seg135:C6299F0A 78 44 ADD R0, PCseg135:C6299F0C 8F 4A LDR R2, unk_C629A14Cseg135:C6299F0E 10 18 ADDS R0, R2, R0seg135:C6299F10 00 68 LDR R0, [R0]seg135:C6299F12 6B 22 92 00 MOVS R2, #0x1ACseg135:C6299F16 82 58 LDR R2, [R0,R2]seg135:C6299F16seg135:C6299F18seg135:C6299F18 30 46 MOV R0, R6seg135:C6299F1A 4F F0 AD FD BL CallIntMethodseg135:C6299F1E 4F F0 7B FD BL GetVmpStrut_j_j__l_S0lSlI$5llll5SI0l$I5IIlOOSlS0Sl$Ill_$__5l0_OllS5$_0seg135:C6299F22 05 46 MOV R5, R0
2、从获取的数据内容还原结构体如下：
strut VMJavaInfo {uint32_t DexCodeindex; // 这是java层传递的指令索引uint32_t CodeSize; // 指令大小uint64_t dexcode; // dexcode指针};
3、通过上面结构体获取dexcode指针，代码如下：
seg135:C629A0F4 loc_C629A0F4seg135:C629A0F4 A8 68 LDR R0, [R5,#8] ; 取dexcodeinfoseg135:C629A0F6 48 60 STR R0, [R1,#4] ; 存dexcodeinfoseg135:C629A0F8 28 68 LDR R0, [R5]seg135:C629A0FA 88 60 STR R0, [R1,#8]seg135:C629A0FC 68 68 LDR R0, [R5,#4]seg135:C629A0FE C8 60 STR R0, [R1,#0xC]seg135:C629A100 04 20 MOVS R0, #4seg135:C629A102 D5 E7 B def_C629A0C0seg135:C629A104 09 98 LDR R0, [SP,#0x24]
dexcode结构体如下：
struct DexCode {u2 registersSize;u2 insSize;u2 outsSize;u2 triesSize;u4 debugInfoOff;u4 insnsSize;u2 insns[1];}
4、根据DexCode结构体获取自定义指令，代码如下：
seg135:C632663A C8 68 LDR R0, [R1,#0xC] ; 取得DexCodeInfo数据seg135:C632663C 8A 69 LDR R2, [R1,#0x18]seg135:C632663E 06 9C LDR R4, [SP,#0x18]seg135:C6326640 E2 61 STR R2, [R4,#0x1C]seg135:C6326642 10 30 ADDS R0, #0x10 ; 定位到DexCodeseg135:C6326644 20 70 STRB R0, [R4] ; 存放DexCode地址seg135:C6326646 02 0E LSRS R2, R0, #0x18seg135:C6326648 E2 70 STRB R2, [R4,#3]seg135:C632664A 02 0C LSRS R2, R0, #0x10seg135:C632664C A2 70 STRB R2, [R4,#2]seg135:C632664E 00 0A LSRS R0, R0, #8seg135:C6326650 60 70 STRB R0, [R4,#1]seg135:C6326652 2B 68 LDR R3, [R5]seg135:C6326654 20 46 MOV R0, R4seg135:C6326656 3E 46 MOV R6, R7seg135:C6326658 2F 46 MOV R7, R5seg135:C632665A 04 9D LDR R5, [SP,#0x10]seg135:C632665C 2A 46 MOV R2, R5seg135:C632665E 4F F0 CB F9 BL VMP_j__lI$$lllIIS0OlSOlI0lllOIllllSIllIO_ll$0I_0SlSIIlIS5$_0 ; R0:DexCode//进入VMPseg135:C6326662 A0 68 LDR R0, [R4,#8]seg135:C6326664 E1 68 LDR R1, [R4,#0xC]
5、解密自定义指令,代码如下：
//解密指令seg135:C635308A 1B 68 LDR R3, [R3] ; 取DEXCodeInfoseg135:C635308C 18 79 LDRB R0, [R3,#4]; 解密DexCode地址seg135:C635308E 59 79 LDRB R1, [R3,#5]seg135:C6353090 09 02 LSLS R1, R1, #8seg135:C6353092 01 43 ORRS R1, R0seg135:C6353094 98 79 LDRB R0, [R3,#6]seg135:C6353096 DA 79 LDRB R2, [R3,#7]seg135:C6353098 12 02 LSLS R2, R2, #8seg135:C635309A 02 43 ORRS R2, R0seg135:C635309C 10 04 LSLS R0, R2, #0x10seg135:C635309E 08 43 ORRS R0, R1seg135:C63530A0 5E 4C LDR R4, unk_C635321Cseg135:C63530A2 6C 44 ADD R4, SPseg135:C63530A4 20 60 STR R0, [R4]seg135:C63530A6 18 78 LDRB R0, [R3]seg135:C63530A8 59 78 LDRB R1, [R3,#1]seg135:C63530AA 09 02 LSLS R1, R1, #8seg135:C63530AC 01 43 ORRS R1, R0seg135:C63530AE 98 78 LDRB R0, [R3,#2]seg135:C63530B0 DA 78 LDRB R2, [R3,#3]seg135:C63530B2 12 02 LSLS R2, R2, #8seg135:C63530B4 02 43 ORRS R2, R0seg135:C63530B6 12 04 LSLS R2, R2, #0x10seg135:C63530B8 0A 43 ORRS R2, R1 ; 得到解密的DexCode地址seg135:C63530BA 36 4C LDR R4, loc_C6353194seg135:C63530BC 6C 44 ADD R4, SP//解密指令seg135:C62B5948 1B 68 LDR R3, [R3] ; 取DexCode地址seg135:C62B594A 59 1A SUBS R1, R3, R1seg135:C62B594C 49 00 LSLS R1, R1, #1seg135:C62B594E 03 22 MOVS R2, #3seg135:C62B5950 D2 43 MVNS R2, R2seg135:C62B5952 0A 40 ANDS R2, R1seg135:C62B5954 8E 49 LDR R1, =0x8F0seg135:C62B5956 69 44 ADD R1, SPseg135:C62B5958 09 68 LDR R1, [R1]seg135:C62B595A C9 68 LDR R1, [R1,#0xC]seg135:C62B595C 89 18 ADDS R1, R1, R2seg135:C62B595E 09 68 LDR R1, [R1] ; 取密钥seg135:C62B5960 1A 88 LDRH R2, [R3] ; 取指令seg135:C62B5962 4A 40 EORS R2, R1 ; 解密seg135:C62B5964 8B 4B LDR R3, =0x904seg135:C62B5966 6B 44 ADD R3, SPseg135:C62B5968 1A 60 STR R2, [R3] ; 存放指令
6、VMP解释执行，代码如下:
//根据解密出来的指令计算对应的handle地址eg135:C62B5968 1A 60 STR R2, [R3] ; 存放指令seg135:C62B596A FF 21 MOVS R1, #0xFFseg135:C62B596C 11 40 ANDS R1, R2seg135:C62B596E 89 00 LSLS R1, R1, #2seg135:C62B5970 40 18 ADDS R0, R0, R1 ; 根据指令计算handle偏移seg135:C62B5972 00 68 LDR R0, [R0] ; 取handleseg135:C62B5974 81 4F LDR R7, =0x940seg135:C62B5976 6F 44 ADD R7, SPseg135:C62B5978 3F 68 LDR R7, [R7]seg135:C62B597A 87 46 MOV PC, R0 ; 跳到对应的handle执行//调用JNI接口调用java方法seg135:C62C2466 5D 20 80 00 MOVS R0, #0x174seg135:C62C246A 51 4D LDR R5, =0x90Cseg135:C62C246C 6D 44 ADD R5, SPseg135:C62C246E 2D 68 LDR R5, [R5]seg135:C62C2470 29 68 LDR R1, [R5]seg135:C62C2472 0C 58 LDR R4, [R1,R0]seg135:C62C2474 4F 48 LDR R0, =0x9A8seg135:C62C2476 68 44 ADD R0, SPseg135:C62C2478 69 46 MOV R1, SPseg135:C62C247A 08 60 STR R0, [R1]seg135:C62C247C 28 46 MOV R0, R5seg135:C62C247E 3F 49 LDR R1, =0x8E8seg135:C62C2480 69 44 ADD R1, SPseg135:C62C2482 09 68 LDR R1, [R1]seg135:C62C2484 4D 4A LDR R2, =0x8E4seg135:C62C2486 6A 44 ADD R2, SPseg135:C62C2488 12 68 LDR R2, [R2]seg135:C62C248A 45 4B LDR R3, =0x8E0seg135:C62C248C 6B 44 ADD R3, SPseg135:C62C248E 1B 68 LDR R3, [R3]seg135:C62C2490seg135:C62C2490 A0 47 BLX R4 ; CallNonvirtualVoidMethodAseg135:C62C2492 4F 48 LDR R0, =0xC566
7、循环取指令解密指令到跳转到对应Handle执行的模板代码如下：
seg135:C62A78E2 A4 48 LDR R0, =(_GLOBAL_OFFSET_TABLE_ - 0xC62A78E8)seg135:C62A78E4 78 44 ADD R0, PCseg135:C62A78E6 97 49 LDR R1, =0xFFFFFA84seg135:C62A78E8 08 18 ADDS R0, R1, R0seg135:C62A78EA 93 49 LDR R1, unk_C62A7B38seg135:C62A78EC 69 44 ADD R1, SPseg135:C62A78EE 09 68 LDR R1, [R1] ; 指令基址seg135:C62A78F0 7B 4B LDR R3, =0x910seg135:C62A78F2 6B 44 ADD R3, SPseg135:C62A78F4 1B 68 LDR R3, [R3] ; 当前要取指令的基址seg135:C62A78F6 59 1A SUBS R1, R3, R1 ; 求也取指令的长度seg135:C62A78F8 49 00 LSLS R1, R1, #1seg135:C62A78FAseg135:C62A78FA loc_C62A78FAseg135:C62A78FA 03 22 MOVS R2, #3seg135:C62A78FC D2 43 MVNS R2, R2 ; handle基地加上指令计算得到的偏移seg135:C62A78FE 0A 40 ANDS R2, R1seg135:C62A7900 91 49 LDR R1, =0x8F0seg135:C62A7902seg135:C62A7902 loc_C62A7902seg135:C62A7902 69 44 ADD R1, SPseg135:C62A7904 09 68 LDR R1, [R1]seg135:C62A7906 C9 68 LDR R1, [R1,#0xC]seg135:C62A7908 89 18 ADDS R1, R1, R2seg135:C62A790A 09 68 LDR R1, [R1] ; 取密钥seg135:C62A790C 1A 88 LDRH R2, [R3] ; 取指令seg135:C62A790E 4A 40 EORS R2, R1 ; 解密指令seg135:C62A7910 70 4B LDR R3, loc_C62A7AD4seg135:C62A7912 6B 44 ADD R3, SPseg135:C62A7914 1A 60 STR R2, [R3] ; 存指令seg135:C62A7916 FF 21 MOVS R1, #0xFFseg135:C62A7918 11 40 ANDS R1, R2seg135:C62A791A 89 00 LSLS R1, R1, #2seg135:C62A791Cseg135:C62A791C loc_C62A791Cseg135:C62A791C 40 18 ADDS R0, R0, R1 ; handle基地加上指令计算得到的偏移seg135:C62A791E 00 68 LDR R0, [R0] ; 取指令对应的handleseg135:C62A7920 75 4F LDR R7, loc_C62A7AF8seg135:C62A7922 6F 44 ADD R7, SPseg135:C62A7924 3F 68 LDR R7, [R7]seg135:C62A7926 87 46 MOV PC, R0 ; 跳到handle执行seg135:C62A7928 93 4E LDR R6, =0x42D
8、指令模拟过程
一条VMP指令：
48 10 10 1948 10 ->解密后 10 8E10 19->字符串索引
上面指令是设置BaseEntity中的code字段值(int类型)，代码模拟如下：
seg135:C62D16DA 01 9E LDR R6, [SP,#0x40+var_3C]seg135:C62D16DC 31 68 LDR R1, [R6]seg135:C62D16DE 20 68 LDR R0, [R4]seg135:C62D16E0 82 69 LDR R2, [R0,#0x18]seg135:C62D16E2 20 46 MOV R0, R4seg135:C62D16E4 90 47 BLX R2 ; FindClassseg135:C62D16E6 07 46 MOV R7, R0seg135:C62D16E8 09 97 STR R7, [SP,#0x40+var_1C]seg135:C62D16EA 2F 20 C0 00 MOVS R0, #0x178seg135:C62D16EE 21 68 LDR R1, [R4]seg135:C62D16F0 0D 58 LDR R5, [R1,R0]seg135:C62D16F2 73 68 LDR R3, [R6,#4]seg135:C62D16F4 B2 68 LDR R2, [R6,#8]seg135:C62D16F6 20 46 MOV R0, R4seg135:C62D16F8 39 46 MOV R1, R7seg135:C62D16FA A8 47 BLX R5 ; GetFieldIDseg135:C62D16FC 08 90 STR R0, [SP,#0x40+var_20]seg135:C62D16FE 05 27 MOVS R7, #5seg135:C62D1700 02 21 MOVS R1, #2seg135:C62D1702 00 28 CMP R0, #0seg135:C62D1704 96 D0 BEQ loc_C62D1634seg135:C62D1706 0F 46 MOV R7, R1seg135:C62D1708 94 E7 B loc_C62D1634seg135:C62D1692 6D 20 80 00 MOVS R0, #0x1B4seg135:C62D1696 21 68 LDR R1, [R4]seg135:C62D1698 0F 58 LDR R7, [R1,R0]seg135:C62D169A 20 46 MOV R0, R4seg135:C62D169C 06 99 LDR R1, [SP,#0x40+var_28]seg135:C62D169E 08 9A LDR R2, [SP,#0x40+var_20]seg135:C62D16A0 07 9B LDR R3, [SP,#0x40+var_24]seg135:C62D16A2 B8 47 BLX R7 ; SetIntFieldseg135:C62D16A4 2F 46 MOV R7, R5
其它指令也是类似的解释过程进行模拟执行。
五、总结
梆梆企业定制版主要功能与上面产品介绍中功能相同，主要是DEX文件加壳保护、DEX抽取加密、DEX虚拟化保护(VMP)、多Dex加固保护、SO文件加壳保护。壳本身做了加壳与指令混淆，每一个Handle之间都连接着的，再加上流程上混淆，字符串加密，方法名混淆，反调试，检测自动脱壳框架，增加了一定的逆向分析难度。
从Java层到Native层都做了相应的保护，由其是代码虚拟化加上指令混淆抗破解能力还是比较强的，要想完整还原Java代码还是需要花很多的时间与精力，整体而言从个人破解者角度来说安全系数还是比较高的。
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