Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 67832cad8c44ec98…

MALICIOUS

Office (OOXML)

132.7 KB Created: 2021-09-04 13:16:06 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-09-22
MD5: a395e57895d4948d619caf60c7c4b6e2 SHA-1: 44f1fd68af9b2b3e577979b7a890061ee3c4d69a SHA-256: 67832cad8c44ec987de929f6d14d511ffb7743340669d773d435a66ac2eecbd2
160 Risk Score

Malware Insights

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

The OOXML document contains a VBA macro with an Auto_Open subroutine. This macro references 'powershell.exe', indicating an intent to execute a PowerShell command. The heuristic 'OLE_VBA_PCODE_AUTOEXEC_EXEC' further suggests that the VBA code is designed to execute a command like URLDownloadToFile, which is commonly used to download and run secondary payloads. The presence of an Auto_Open macro and the PowerShell execution strongly suggest this document is a malicious attachment designed to initiate a multi-stage attack.

Heuristics 4

  • 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
  • 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.

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) 715 bytes
SHA-256: c0ebcd25a4551455183817ebf4fd55b79e3778afd9ac56aac331f19658ea760b
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub Auto_Open()
    Dim Var As String
    Var = "powershell.exe"
End Sub

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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 16384 bytes
SHA-256: ad30d0b2ee0a703a185d840ba6af749ecae2f277d177acf5ef3f3ed0589ee17a

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