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[原创]蛮犀加固免费版脱壳
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发表于: 2023-9-20 20:49
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样本只作为脱壳学习的一个样本，样本的内部逻辑并没有仔细分析，且样本较为简单，通用性差。本帖仅作为学习记录，欢迎大家一同交流。
首先先来官网看一下免费版包括的内容
上传一个Demo用于加固，Demo反编译结果如下
加固只针对Dex进行，且对类进行抽取，其效果如下
首先Shell创建了Application获取程序的起始控制权，之后在attachBaseContext通过Helper类加载manxi.so文件
之后的步骤都是在So层进行，所以需要对So层进行分析
So通过ollvm进行混淆，首先我们先通过Qiling模拟执行去除最简单的字符串混淆
首先我们需要提取到init_array所有函数起始地址和结束地址，这里我通过IDAPython进行提取
提取到地址之后即可进行模拟执行，监听内存读写，由于字符串解密函数通过OLLVM进行混淆，所以存在对于状态变量的写入，这会导致对内存写入的Hook产生多余的结果，只需要通过判断偏移是否在.data段或者.rodata段即可判断是否对加密字符串进行写入，过滤掉不需要修改的内容后把解密内存写入文件中即可(如果某个函数不能模拟执行只需要从列表中去除即可)
解密之后就可以看到很多敏感字符串，但实际上该程序没有检测Root、Fart，只在程序启动时对Frida检测，也就是说可通过Attach来进行附加
首先需要绕过启动时的Frida检测，奇怪的是我Hook dlopen和android_dlopen_ext都无法获取到libmanxi.so的加载，但是通过Process.enumerateModules()可以得到so，这也导致了后续难以定位到检测的位置和绕过。于是使用魔改Frida https://github.com/Ylarod/Florida/releases (可绕过检测)
简单Hook了一下程序中的SVC指令，通过Radare2的/adj svc可导出所有SVC指令的地址
其中addr是导出的结果，这里只针对openat进行过滤
发现其创建线程不断打开status文件进而查询TracerPID字段
首先尝试Hook LoadMethod进而进行脱壳
然而脱下来的壳依旧只有Shell代码，即便我们通过延迟脱壳(即首先获取DexFile的begin和size，之后通过命令行调用脱壳函数)依旧如此
所以尝试别的办法，首先我们知道整体加固的原理是替换ClassLoader来加载原Dex，而Shell Dex尾部恰好存在着大量数据，可以猜测这就是被加密的Dex。由于Shell加载完成之后会将程序控制权归还给原程序，所以我们可以Hook performLaunchActivity，在Activity启动之前获取系统ClassLoader进而得到其加载的Dex文件进行Dump。经过测试，最后一个覆盖的Dex文件为原Dex
反编译结果如下，可以发现onCreate的方法内容未被填充
所以尝试延迟Dump的时机，通过Hook ArtMethod::Invoke来Dump，最终代码如下
反编译效果如下
import idaapi
import lief
import struct
from pwn import elf, pack, unpack, u64
idaapi.msg_clear()elf_raw = elf.ELF("D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so")
elf_patch = elf.ELF(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)print(elf_raw.entrypoint)
init_array = None
binary = lief.parse(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)for sec in binary.sections:
if sec.name == ".init_array":
init_array = sec
# Read Init_arrayfuncArray = []
funcArray_Address = []
index = 0
while index < init_array.size:
offset = u64(elf_raw.read(init_array.virtual_address + index, 8))
funcArray.append(offset)
index += 8
funcArray.pop()for func in funcArray:
function = []
function.append(func)
function.append(idaapi.get_func(func).end_ea)
funcArray_Address.append(function)
print(funcArray_Address)
import idaapi
import lief
import struct
from pwn import elf, pack, unpack, u64
idaapi.msg_clear()elf_raw = elf.ELF("D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so")
elf_patch = elf.ELF(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)print(elf_raw.entrypoint)
init_array = None
binary = lief.parse(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)for sec in binary.sections:
if sec.name == ".init_array":
init_array = sec
# Read Init_arrayfuncArray = []
funcArray_Address = []
index = 0
while index < init_array.size:
offset = u64(elf_raw.read(init_array.virtual_address + index, 8))
funcArray.append(offset)
index += 8
funcArray.pop()for func in funcArray:
function = []
function.append(func)
function.append(idaapi.get_func(func).end_ea)
funcArray_Address.append(function)
print(funcArray_Address)
import lief
from qiling.os.const import POINTER, UINT, STRING
from qiling import Qiling
from qiling.const import QL_VERBOSE
from qiling.const import QL_INTERCEPT
from qiling import os
from qiling.os.mapper import QlFsMappedObject
import struct
from pwn import elf, pack, unpack, u64
soData = lief.parse("libmanxi.so")
datasec = None
rodatasec = None
for sec in soData.sections:
if sec.name == ".data":
datasec = sec
elif sec.name == ".rodata":
rodatasec = sec
data_str = ""
elf_patch = elf.ELF(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)def write_hook(ql: Qiling, access: int, address: int, size: int, value: int):
Addr = address - base_addr
if (
Addr >= datasec.virtual_address
and Addr <= datasec.virtual_address + datasec.size
) or (
Addr >= rodatasec.virtual_address
and Addr <= rodatasec.virtual_address + rodatasec.size
):
# if value >= 32 and value <= 128:
print(
f"Write Address: {hex(address-base_addr)} Value:{hex(value)} Size:{hex(size)}"
)
if size == 1:
data = ql.pack8(value)
elif size == 2:
data = ql.pack16(value)
elif size == 4:
data = ql.pack32(value)
elif size == 8:
data = ql.pack64(value)
elf_patch.write(Addr, data)
# Read Init_arrayfuncArray = [
[22616, 23116],
[28832, 29460],
[39664, 40264],
[42856, 43124],
[43932, 44020],
[46660, 46664],
[55196, 62940],
[63672, 63756],
[63756, 63840],
[63840, 63924],
[73424, 73428],
[73516, 73600],
[87628, 88064],
[122504, 122588],
[123876, 124208],
[124208, 124292],
[125200, 125288],
[127652, 128176],
[131420, 131828],
[135164, 135876],
[153412, 154708],
[164120, 167816],
[175060, 175332],
[183120, 183124],
[183124, 183128],
[186856, 186940],
[193592, 193732],
[215616, 216696],
[219564, 219648],
[232264, 232352],
[232920, 232924],
[233080, 233352],
[244248, 253964],
[255484, 256504],
[258116, 258424],
[259408, 262080],
[262080, 262432],
[264236, 264696],
[268872, 269224],
[269688, 270484],
[274292, 276648],
[283864, 284264],
[286580, 287280],
[288384, 288656],
[291236, 291596],
[292296, 293676],
[294012, 295272],
[295272, 295520],
[295976, 296248],
[299480, 299788],
[300236, 307192],
[307500, 307504],
[311600, 312672],
[313304, 313308],
[316048, 316052],
[324380, 325624],
[378800, 380220],
[382004, 382008],
[389160, 389520],
[390088, 390092],
[392360, 392444],
[407960, 407964],
[410060, 410064],
[414476, 415160],
[448668, 457116],
[464888, 464972],
[469092, 469444],
[471132, 471388],
[472156, 472160],
[472180, 472264],
[472512, 472596],
[472596, 472680],
[472680, 472684],
[472684, 472772],
[485160, 489068],
[491672, 493608],
[493608, 493692],
[506756, 506988],
[520552, 521200],
[523132, 523532],
[528344, 528576],
[533168, 539904],
[548616, 550592],
[568596, 569860],
[573168, 575808],
[579536, 579792],
[589616, 589620],
[610480, 610484],
[626444, 626916],
[636500, 636504],
[641936, 643184],
[644460, 644464],
[644816, 644820],
[42852, 42856],
]# # Init Binary Fileql = Qiling(
["D:/new/frida-agent-example-main/agent/node_modules/libmanxi.so"],
r"D:/new/rootfs/arm64_android",
verbose=QL_VERBOSE.DISASM,
)base_addr = ql.mem.get_lib_base("libmanxi.so")
str = f"Base Address: {hex(base_addr)}"
ql.hook_mem_write(write_hook)for func in funcArray:
ql.run(func[0] + base_addr, func[1] + base_addr - 4)
elf_patch.save("aaa.so")
import lief
from qiling.os.const import POINTER, UINT, STRING
from qiling import Qiling
from qiling.const import QL_VERBOSE
from qiling.const import QL_INTERCEPT
from qiling import os
from qiling.os.mapper import QlFsMappedObject
import struct
from pwn import elf, pack, unpack, u64
soData = lief.parse("libmanxi.so")
datasec = None
rodatasec = None
for sec in soData.sections:
if sec.name == ".data":
datasec = sec
elif sec.name == ".rodata":
rodatasec = sec
data_str = ""
elf_patch = elf.ELF(
"D:/new/frida-agent-example-main/agent/node_modules/libmanxi_copy.so"
)def write_hook(ql: Qiling, access: int, address: int, size: int, value: int):
Addr = address - base_addr
if (
Addr >= datasec.virtual_address
and Addr <= datasec.virtual_address + datasec.size
) or (
Addr >= rodatasec.virtual_address
and Addr <= rodatasec.virtual_address + rodatasec.size
):
# if value >= 32 and value <= 128:
print(
f"Write Address: {hex(address-base_addr)} Value:{hex(value)} Size:{hex(size)}"
)
if size == 1:
data = ql.pack8(value)
elif size == 2:
data = ql.pack16(value)
elif size == 4:
data = ql.pack32(value)
elif size == 8:
data = ql.pack64(value)
elf_patch.write(Addr, data)
# Read Init_arrayfuncArray = [
[22616, 23116],
[28832, 29460],
[39664, 40264],
[42856, 43124],
[43932, 44020],
[46660, 46664],
[55196, 62940],
[63672, 63756],
[63756, 63840],
[63840, 63924],
[73424, 73428],
[73516, 73600],
[87628, 88064],
[122504, 122588],
[123876, 124208],
[124208, 124292],
[125200, 125288],
[127652, 128176],
[131420, 131828],
[135164, 135876],
[153412, 154708],
[164120, 167816],
[175060, 175332],
[183120, 183124],
[183124, 183128],
[186856, 186940],
[193592, 193732],
[215616, 216696],
[219564, 219648],
[232264, 232352],
[232920, 232924],
[233080, 233352],
[244248, 253964],
[255484, 256504],
[258116, 258424],
[259408, 262080],
[262080, 262432],
[264236, 264696],
[268872, 269224],
[269688, 270484],
[274292, 276648],
[283864, 284264],
[286580, 287280],
[288384, 288656],
[291236, 291596],
[292296, 293676],
[294012, 295272],
[295272, 295520],
[295976, 296248],
[299480, 299788],
[300236, 307192],
[307500, 307504],
[311600, 312672],
[313304, 313308],
[316048, 316052],
[324380, 325624],
[378800, 380220],
[382004, 382008],
[389160, 389520],
[390088, 390092],
[392360, 392444],
[407960, 407964],
[410060, 410064],
[414476, 415160],
[448668, 457116],
[464888, 464972],
[469092, 469444],
[471132, 471388],
[472156, 472160],
[472180, 472264],
[472512, 472596],
[472596, 472680],
[472680, 472684],
[472684, 472772],
[485160, 489068],
[491672, 493608],
[493608, 493692],
[506756, 506988],
[520552, 521200],
[523132, 523532],
[528344, 528576],
[533168, 539904],
[548616, 550592],
[568596, 569860],
[573168, 575808],
[579536, 579792],
[589616, 589620],
[610480, 610484],
[626444, 626916],
[636500, 636504],
[641936, 643184],
[644460, 644464],
[644816, 644820],
[42852, 42856],
]# # Init Binary Fileql = Qiling(
["D:/new/frida-agent-example-main/agent/node_modules/libmanxi.so"],
r"D:/new/rootfs/arm64_android",
verbose=QL_VERBOSE.DISASM,
)base_addr = ql.mem.get_lib_base("libmanxi.so")
str = f"Base Address: {hex(base_addr)}"
ql.hook_mem_write(write_hook)for func in funcArray:
ql.run(func[0] + base_addr, func[1] + base_addr - 4)
elf_patch.save("aaa.so")
function hook_svc() {
console.log("=====Hook SVC=====")
var base_addr = Module.findBaseAddress("libmanxi.so");
addr.forEach(function (svc) {
var offset = `0x` + svc.offset.toString(16)
Interceptor.attach(base_addr.add(offset), {
onEnter: function (args) {
if (this.context.x8 == 0x38) {
console.log("Openat:" + ptr(this.context.x1).readCString())
}
},
onLeave: function (retval) {
}
})
})
}function hook_svc() {
[培训]内核驱动高级班，冲击BAT一流互联网大厂工作，每周日13:00-18:00直播授课
最后于 2023-9-20 21:10
被Gift1a编辑
，原因：
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哦嗨哟~s0rry! |
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