Microsoft MsMpEng – Multiple Crashes While Scanning Malformed Files

• Exploit Database
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• 作者： Google Security Research
  日期： 2017-05-29
• 类别：

  • dos
  平台：

  • windows
• 来源：https://www.exploit-db.com/exploits/42081/
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  Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1261   A detailed introduction to MsMpEng can be found inissue #1252 , so I will skip the background story here.   Through fuzzing, we have discovered a number of ways to crash the service (and specifically code in the mpengine.dll module), by feeding it with malformed input testcases to scan. A summary of our findings is shown in the table below:   +==============+===================================+==========================+=============+====================================================+=============================================+ | Name | Type| Requirements | Access Type |Observed symbol |Comments | +==============+===================================+==========================+=============+====================================================+=============================================+ | corruption_1 | Heap buffer overflow| PageHeap for MpMsEng.exe | - | free() called by NET_thread_ctx_t__FreeState_void_ | One-byte overflow.| +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | corruption_2 | Heap corruption | PageHeap for MpMsEng.exe | - | free() called by CRsaPublicKey__Decrypt_uchar| May crash in other ways, e.g. invalid read. | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | corruption_3 | Unspecified memory corruption (?) | -| - | netvm_parse_routine_netinvoke_handle_t | Different crashes with/out PageHeap.| +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | null_1 | NULL Pointer Dereference| -| READ| nUFSP_pdf__handleXFA_PDF_Value | | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | null_2 | NULL Pointer Dereference| -| READ| nUFSP_pdf__expandObjectStreams_void| | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | null_3 | NULL Pointer Dereference| -| READ| NET_context_unsigned | | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | null_4 | NULL Pointer Dereference| -| READ| nUFSP_pdf__expandObjectStreams_void_ | Similar to null_2, may be the same bug. | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | div_by_zero| Division by zero| -| - | x86_code_cost__get_cost_int| | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+ | recursion| Deep/infinite recursion | -| - | __EH_prolog3_catch_GS| | +--------------+-----------------------------------+--------------------------+-------------+----------------------------------------------------+---------------------------------------------+   The "corruption_1-3" issues are the most important ones, as they represent memory corruption problems and could potentially lead to execution of arbitrary code. On the other hand, "null_1-4", "div_by_zero" and "recursion" are low severity bugs that can only be used to bring the service process down. We have verified that all listed crashes occur on Windows 7 as soon as an offending sample is saved to disk and discovered by MsMpEng. For "corruption_1-2", the PageHeap mechanism must be enabled for the MsMpEng.exe program in order to reliably observe the unhandled exception.   Attached is a ZIP archive (password: "mpengbugs") with up to 3 testcases for each of the 9 unique crashes.     Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/42081.zip