Symantec AntiVirus – Missing Bounds Checks in dec2zip ALPkOldFormatDecompressor::UnShrink

• Exploit Database
• 12 阅读

• 作者： Google Security Research
  日期： 2016-06-29
• 类别：

  • dos
  平台：

  • multiple
• 来源：https://www.exploit-db.com/exploits/40036/

• Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=821
  
  A major component of the Symantec Antivirus scan engine is the "Decomposer", responsible for unpacking various archive formats such as ZIP, RAR, and so on. The decomposer runs as NT AUTHORITY\SYSTEM on Windows, and root on Linux and Mac. Simple fuzzing of zip archives discovered missing bounds checks in the routine ALPkOldFormatDecompressor::UnShrink, used to decode Zip archives. 
  
  The routine uses a 16bit value read from the file to index a 256 element array without any bounds checking, the attached testcase should demonstrate this reliably. I have verified this on the following products:
  
  Norton Antivirus, Windows
  Symantec Endpoint Protection, Linux and Windows
  Symantec Scan Engine, Linux and Windows
  
  
  (534.700): Access violation - code c0000005 (!!! second chance !!!)
  eax=00003000 ebx=00003000 ecx=00003000 edx=00002000 esi=16adeb58 edi=16ad8b1b
  eip=6ba47ec3 esp=16ad6af0 ebp=16adeb20 iopl=0 nv up ei pl nz na pe nc
  cs=0023ss=002bds=002bes=002bfs=0053gs=002b efl=00010206
  ccScanw!filelengthi64+0x3af63:
  6ba47ec3 66399445fcbfffff cmp word ptr [ebp+eax*2-4004h],dx ss:002b:16ae0b1c=????
  0:071> ub
  ccScanw!filelengthi64+0x3af3f:
  6ba47e9f 8bb5ec7fffffmov esi,dword ptr [ebp-8014h]
  6ba47ea5 8bc7mov eax,edi
  6ba47ea7 8985e07fffffmov dword ptr [ebp-8020h],eax
  6ba47ead e96d010000jmp ccScanw!filelengthi64+0x3b0bf (6ba4801f)
  6ba47eb2 0fbfc3movsx eax,bx
  6ba47eb5 ba00200000mov edx,2000h
  6ba47eba 8dbdfb9ffffflea edi,[ebp-6005h]
  6ba47ec0 0fb7cbmovzx ecx,bx
  0:071> lmv m ccScanw
  startendmodule name
  6b930000 6bb5f000 ccScanw(export symbols) C:\Program Files (x86)\Norton Security\Engine\22.6.0.142\ccScanw.dll
  Loaded symbol image file: C:\Program Files (x86)\Norton Security\Engine\22.6.0.142\ccScanw.dll
  Image path: C:\Program Files (x86)\Norton Security\Engine\22.6.0.142\ccScanw.dll
  Image name: ccScanw.dll
  Timestamp:Tue Jan 26 13:51:55 2016 (56A7EA7B)
  CheckSum: 0022B3ED
  ImageSize:0022F000
  File version: 13.1.2.19
  Product version:13.1.2.19
  File flags: 0 (Mask 3F)
  File OS:40004 NT Win32
  File type:1.0 App
  File date:00000000.00000000
  Translations: 0409.04b0
  CompanyName:Symantec Corporation
  ProductName:Symantec Security Technologies
  InternalName: ccScan
  OriginalFilename: CCSCAN.DLL
  ProductVersion: 13.1.2.19
  FileVersion:13.1.2.19
  FileDescription:Symantec Scan Engine
  LegalCopyright: Copyright (c) 2015 Symantec Corporation. All rights reserved.
  
  
  Proof of Concept:
  https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40036.zip