Symantec AntiVirus – TNEF Decoder Integer Overflow

• Exploit Database
• 18 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/40035/

• Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=819
  
  Simple fuzzing found an integer overflow in the dec2tnef library. This allocation from Attachment::setDataFromAttachment() doesn't verify that the attacker controlled value doesn't wrap:
  
  .text:000227B8 8D 42 01 lea eax, [edx+1]
  .text:000227BB 89 85 68 FF FF+mov [ebp+var_98], eax
  .text:000227C1 8B 83 CC FF FF+mov eax, ds:(_ZSt7nothrow_ptr - 42CFCh)[ebx]
  .text:000227C7 89 44 24 04mov [esp+4], eax
  .text:000227CB 8B 85 68 FF FF+mov eax, [ebp+var_98]
  .text:000227D1 C1 E0 02 shl eax, 2
  .text:000227D4 89 04 24 mov [esp], eax
  .text:000227D7 89 95 5C FF FF+mov [ebp+src], edx
  .text:000227DD 89 8D 58 FF FF+mov [ebp+var_A8], ecx
  .text:000227E3 E8 54 22 FE FF call__ZnajRKSt9nothrow_t ; operator new[](uint,std::nothrow_t const&)
  
  That's (count + 1) * 4, without any checking that will succeed. The attached testcase reaches this code on Symantec Scan Engine, I'm not sure which other products use this code.
  
  (gdb) bt
  #10x07e88816 in Attachment::setDataFromAttachment(Item&) () from definitions/Decomposer/libdec2tnef.so
  #20x07e88abc in Attachment::setAttribute(Item&) () from definitions/Decomposer/libdec2tnef.so
  #30x07e8a1b4 in TNEFObject::getAttachments(_IO_FILE*, MList&) () from definitions/Decomposer/libdec2tnef.so
  #40x07e6c1d6 in CTNEFArchive::Open(char const*) () from definitions/Decomposer/libdec2tnef.so
  #50x07e6ae5f in CTNEFEngine::OpenArchive(CTNEFArchive*, bool*) () from definitions/Decomposer/libdec2tnef.so
  #60x07e6b8c0 in CTNEFEngine::Process(IDecomposerEx*, IDecContainerObjectEx*, IDecEventSink*, unsigned short*, char*, bool*, bool*) () from definitions/Decomposer/libdec2tnef.so
  #70x063d07b5 in CDecomposer::DecProcess(IDecObject*, IDecEventSink*, IDecIOCB*, unsigned short*, char*) () 
  #80x063d13cb in CDecomposer::Process(IDecObject*, IDecEventSink*, IDecIOCB*, unsigned short*, char*) ()
  
  
  Proof of Concept:
  https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40035.zip