目录
- 64位下读取SSDT表并且获取SSDT函数
- 一丶读取SSDT表 (KeServiceDescriptorTable)
- 1.1 原理
- 1.2 手动获取SSDT表
- 1.2.1 重点1 了解引用流程以及其它方式寻找SSDT表的方式
- 1.2.2 重要点2 获取SSDT表以及Shadow表位置
- 1.2.3 重要点3 SSDT表的加密获取以及使用
- 二丶两种方式实现获取SSDT表
- 2.1 常规方式获取SSDT表.
- 2.2 通过API寻找方式来找寻SSDT
- 一丶读取SSDT表 (KeServiceDescriptorTable)
64位下读取SSDT表并且获取SSDT函数
一丶读取SSDT表 (KeServiceDescriptorTable)
1.1 原理
在64位系统下我们可以通过读取msr 寄存器来获取内核函数入口. msr在开启内核隔离模式下获取的是 KiSystemCall64Shadow 而在未开启内核模式下则是获取的 KiSystemCall64
1.2 手动获取SSDT表
windbg链接双机调试. 输入命令 rdmsr 0xC0000082 即可看到内核函数入口. 反汇编此函数的地址往下找即可看到获取SSDT表位置代码.
这里我以IDA举例子 如果你能反汇编内核文件,并且为其下载好符号.则在函数列表中直接搜索 KiSystemCall64 即可. 如下:
观看其位置反汇编代码:
代码语言：javascript复制.text:00000001401D2980 KiSystemServiceStart: ; DATA XREF: KiServiceInternal 5A↑o 重要点1
.text:00000001401D2980
.text:00000001401D2980 48 89 A3 90 00 00 00 mov [rbx 90h], rsp
.text:00000001401D2987 8B F8 mov edi, eax
.text:00000001401D2989 C1 EF 07 shr edi, 7
.text:00000001401D298C 83 E7 20 and edi, 20h
.text:00000001401D298F 25 FF 0F 00 00 and eax, 0FFFh
.text:00000001401D2994
.text:00000001401D2994 KiSystemServiceRepeat:
.text:00000001401D2994 4C 8D 15 E5 9E 3B 00 lea r10, KeServiceDescriptorTable_0 重要点2
.text:00000001401D299B 4C 8D 1D DE 20 3A 00 lea r11, KeServiceDescriptorTableShadow
.text:00000001401D29A2 F7 43 78 80 00 00 00 test dword ptr [rbx 78h], 80h
.text:00000001401D29A9 74 13 jz short loc_1401D29BE
.text:00000001401D29AB F7 43 78 00 00 20 00 test dword ptr [rbx 78h], 200000h
.text:00000001401D29B2 74 07 jz short loc_1401D29BB
.text:00000001401D29B4 4C 8D 1D 05 21 3A 00 lea r11, KeServiceDescriptorTableFilter
.text:00000001401D29BB
.text:00000001401D29BB loc_1401D29BB:
.text:00000001401D29BB 4D 8B D3 mov r10, r11
.text:00000001401D29BE
.text:00000001401D29BE loc_1401D29BE:
.text:00000001401D29BE 41 3B 44 3A 10 cmp eax, [r10 rdi 10h]
.text:00000001401D29C3 0F 83 2C 05 00 00 jnb loc_1401D2EF5
.text:00000001401D29C9 4D 8B 14 3A mov r10, [r10 rdi]
.text:00000001401D29CD 4D 63 1C 82 movsxd r11, dword ptr [r10 rax*4]
.text:00000001401D29D1 49 8B C3 mov rax, r11
.text:00000001401D29D4 49 C1 FB 04 sar r11, 4 重要点3
.text:00000001401D29D8 4D 03 D3 add r10, r11
.text:00000001401D29DB 83 FF 20 cmp edi, 20h ; ' '
.text:00000001401D29DE 75 50 jnz short loc_1401D2A30
.text:00000001401D29E0 4C 8B 9B F0 00 00 00 mov r11, [rbx 0F0h]上述汇编描述了三个重要点
1.2.1 重点1 了解引用流程以及其它方式寻找SSDT表的方式
KiServiceInternal 与 KiSystemServiceStart
这里要了解下SSDT表起始获取是 KiSystemServiceStart 而 KiServiceInternal 则会引用 KiSystemServiceStart 那么为什么讲一下这里. 因为在内核中我们可以通过任意一个内核函数来找到 KiServiceInternal 然后通过 KiServiceInternal 来找到 KiSystemServiceStart 然后通过 KiSystemServiceStart 来定位SSDT表或者SSDTShadow表
例子:
1.2.2 重要点2 获取SSDT表以及Shadow表位置
重要点2位置的两行代码则是获取SSDT表与Shadow表. 表示为如下:
代码语言：javascript复制.text:00000001401D2994 KiSystemServiceRepeat:
.text:00000001401D2994 4C 8D 15 E5 9E 3B 00 lea r10, KeServiceDescriptorTable_0
.text:00000001401D299B 4C 8D 1D DE 20 3A 00 lea r11, KeServiceDescriptorTableShadow特征码分别为 0x4c 0x8d 0x15 ---> Get SSDT 0x4c 0x8d 0x1d ---> Get SSDTShadow
1.2.3 重要点3 SSDT表的加密获取以及使用
这里是重点在32位下的SSDT表你可以任意HOOK 而到了64位下你则不能 "HOOK" 了 因为你的函数定义不在同一个4GB空间中.所以不能直接跳转使用.而为什么这样. 就是重要点三所在的汇编所体现的.
代码语言：javascript复制.text:00000001401D29BE 41 3B 44 3A 10 cmp eax, [r10 rdi 10h]
.text:00000001401D29C3 0F 83 2C 05 00 00 jnb loc_1401D2EF5
.text:00000001401D29C9 4D 8B 14 3A mov r10, [r10 rdi]
.text:00000001401D29CD 4D 63 1C 82 movsxd r11, dword ptr [r10 rax*4] offset = SSDT[sizeof(int) * index]
.text:00000001401D29D1 49 8B C3 mov rax, r11
.text:00000001401D29D4 49 C1 FB 04 sar r11, 4 offset = offset >> 4
.text:00000001401D29D8 4D 03 D3 add r10, r11 pfn = ssdt.base offset = 实际的函数地址
.text:00000001401D29DB 83 FF 20 cmp edi, 20h ; ' '
.text:00000001401D29DE 75 50 jnz short loc_1401D2A30
.text:00000001401D29E0 4C 8B 9B F0 00 00 00 mov r11, [rbx 0F0h]这里有一个右移的操作.观看汇编反汇编为高级代码则如下:
代码语言：javascript复制offset = SSDT[index * 4] ;
offset = offset >> 4 ; 亦或者等价于 offset = offset / 16
pfnAddr = ssdt.base offset;在内存中如下:
代码语言：javascript复制1: kd> dq 0xfffff8067758c880 查看SSDT表
fffff806`7758c880 fffff806`77424cc0 00000000`00000000
fffff806`7758c890 00000000`000001d0 fffff806`77425404
fffff806`7758c8a0 00000000`00000000 00000000`00000000
fffff806`7758c8b0 00000000`00000000 00000000`00000000
fffff806`7758c8c0 fffff806`771cc8c0 fffff806`771ccc00
fffff806`7758c8d0 fffff806`771d1580 fffff806`771d18c0
fffff806`7758c8e0 fffff806`771d1c00 fffff806`771d2640
fffff806`7758c8f0 fffff806`771d2180 00000000`00000000
1: kd> dd fffff806`77424cc0 查看SSDT表数组中的内容
fffff806`77424cc0 fced6104 fcf76a00 02b81c02 04749800
fffff806`77424cd0 01ce2700 fd9fe900 01c03705 01c38c06
fffff806`77424ce0 0220d205 0288b301 028aaa00 01a96400
fffff806`77424cf0 01e26500 01c27900 028a4600 01cc7c00
fffff806`77424d00 0221e201 01bf7001 0295a500 01fde702
fffff806`77424d10 01a86600 01e0a200 01d09201 01ce8102
fffff806`77424d20 022b9002 01f4a401 01fbc601 02871e05
fffff806`77424d30 0228ee00 028bcf03 02362000 0461a300我们可以手动计算出地址. 根据上面反汇编的代码得出
offset = *(PLONG)SSDT uid * 4 = fced6104 注意offset不是ULONG类型. 而是LONG类型. 偏移记录的是整数 而不是无符号整数.否则你计算出的基地址就会加10000000的数据.导致计算出错
offset = offset >> 4;
pfnAddr = (PULONGLONG)(offset ssdt.base) ==> offset 0xfffff80677424cc0 最终计算出的地址为: pfnAddr = 0xfffff806771122d0
查看pcHunter
核心代码:
提供了两种方式.指针或者数组寻址 都是可以可以的.数组那块我是转换为了ULONG来操作的 因为: char * ary; offset = ary sizeof(type) * index 就是数组寻址. 可以优化为: PULONG ssdt; offset = ssdt[index];
代码语言：javascript复制PVOID Cssdt::GetProcById(ULONG uId)
{
PKSERVICE_TABLE_DESCRIPTOR pSsdt = NULL;
PULONGLONG pFunctionAddr = NULL;
PUCHAR ssdtbase = NULL;
LONG offset = 0;
pSsdt = this->GetSsdtBaseByKernelFunction((PVOID)ZwCreateFile, 0x500);
if (pSsdt == NULL)
{
return NULL;
}
//calc function
//pointer get addr
// ssdtbase = (PUCHAR)pSsdt->Base;
// offset = (LONG) * (PULONG)(ssdtbase uId * 4);
// offset = (LONG)offset >> 4;
// pFunctionAddr = (PULONGLONG)(offset ssdtbase);
//array get addr
ssdtbase = (PUCHAR)pSsdt->Base;
offset = (LONG)((PULONG)ssdtbase)[uId];
offset = (LONG)offset >> 4;
pFunctionAddr = (PULONGLONG)(offset ssdtbase);
return pFunctionAddr;
}二丶两种方式实现获取SSDT表
2.1 常规方式获取SSDT表.
暂时待写
2.2 通过API寻找方式来找寻SSDT
.h
代码语言：javascript复制#pragma once
#ifdef __cplusplus
extern "C"
{
#endif
#include <ntifs.h>
#include <ntddk.h>
#include <Ntstrsafe.h>
#include "ntimage.h"
#ifdef __cplusplus
}
#endif
#ifdef _AMD64_
typedef struct _KSERVICE_TABLE_DESCRIPTOR
{
PULONG_PTR Base;
PULONG_PTR Count;
PULONG_PTR Limit;
PULONG_PTR Number;
} KSERVICE_TABLE_DESCRIPTOR, *PKSERVICE_TABLE_DESCRIPTOR;
#else
#endif
class Cssdt
{
private:
/* data */
public:
Cssdt(/* args */);
~Cssdt();
public:
PVOID GetProcById(ULONG uId);
PKSERVICE_TABLE_DESCRIPTOR GetSsdtBase();
PKSERVICE_TABLE_DESCRIPTOR GetSsdtBaseByKernelFunction(PVOID pfnKernelFunction, ULONG findSize);
};.cpp
代码语言：javascript复制#include "ssdt.h"
Cssdt::Cssdt(/* args */)
{
}
Cssdt::~Cssdt()
{
}
PVOID Cssdt::GetProcById(ULONG uId)
{
PKSERVICE_TABLE_DESCRIPTOR pSsdt = NULL;
PULONGLONG pFunctionAddr = NULL;
PUCHAR ssdtbase = NULL;
LONG offset = 0;
pSsdt = this->GetSsdtBaseByKernelFunction((PVOID)ZwCreateFile, 0x500);
if (pSsdt == NULL)
{
return NULL;
}
//calc function
//pointer get addr
// ssdtbase = (PUCHAR)pSsdt->Base;
// offset = (LONG) * (PULONG)(ssdtbase uId * 4);
// offset = (LONG)offset >> 4;
// pFunctionAddr = (PULONGLONG)(offset ssdtbase);
//array get addr
ssdtbase = (PUCHAR)pSsdt->Base;
offset = (LONG)((PULONG)ssdtbase)[uId];
offset = (LONG)offset >> 4;
pFunctionAddr = (PULONGLONG)(offset ssdtbase);
return pFunctionAddr;
}
PKSERVICE_TABLE_DESCRIPTOR Cssdt::GetSsdtBaseByKernelFunction(PVOID pfnKernelFunction, ULONG findSize)
{
BOOLEAN bIsFind = FALSE;
PVOID pFindAddress = NULL;
ULONG uSearchStartIndex = 0;
PUCHAR pSearchAddress = (PUCHAR)pfnKernelFunction;
PUCHAR pfnKiServiceInternal = NULL;
PKSERVICE_TABLE_DESCRIPTOR pSsdtInfo = NULL;
if (pfnKernelFunction == NULL)
{
return NULL;
}
if (!MmIsAddressValid(pfnKernelFunction))
{
return NULL;
}
//查找函数中的 .text:00000001401BD9E9 E9 D2 4B 01 00 jmp KiServiceInternal
for (uSearchStartIndex = 0; uSearchStartIndex < findSize; uSearchStartIndex )
{
if (MmIsAddressValid(&pSearchAddress[uSearchStartIndex]))
{
if (pSearchAddress[uSearchStartIndex] == 0xE9)
{
//取出它记录的偏移地址. 公式: DstProc = offset len(opcode) CurrendRip
if (MmIsAddressValid((PULONG)&pSearchAddress[uSearchStartIndex 1]))
{
ULONG offset = *(PULONG)&pSearchAddress[uSearchStartIndex 1];
PUCHAR pCurRip = &pSearchAddress[uSearchStartIndex];
pfnKiServiceInternal = pCurRip offset 5;
break;
}
}
}
}
if (pfnKiServiceInternal == NULL)
{
return NULL;
}
for (uSearchStartIndex = 0; uSearchStartIndex < findSize; uSearchStartIndex )
{
if (MmIsAddressValid((PULONGLONG)&pfnKiServiceInternal[uSearchStartIndex]))
{
if (
pfnKiServiceInternal[uSearchStartIndex] == 0x4C && pfnKiServiceInternal[uSearchStartIndex 1] == 0x8D && pfnKiServiceInternal[uSearchStartIndex 2] == 0x15)
{
ULONG offset = *(PULONG)&pfnKiServiceInternal[uSearchStartIndex 3];
PUCHAR pCurRip = &pfnKiServiceInternal[uSearchStartIndex];
pSsdtInfo = (PKSERVICE_TABLE_DESCRIPTOR)(pCurRip offset 7);
break;
}
}
}
//Shadow 同上
return pSsdtInfo;
}
PKSERVICE_TABLE_DESCRIPTOR Cssdt::GetSsdtBase()
{
return NULL;
}
