Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 499cbd245d9f9f72…

MALICIOUS

Office (OOXML)

3.9 KB First seen: 2021-06-20
MD5: ff1d069fee7c39a68cc165c1d4dac3f2 SHA-1: c2365c5bb7a16e660d5009d077e292754664c529 SHA-256: 499cbd245d9f9f727abd74633f1c0cccfcb9b2f68a6250079114c8e8bb983861
240 Risk Score

Malware Insights

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

The sample is an Office document containing a Workbook_Open VBA macro. This macro uses the Shell() function to execute 'calc.exe', indicating a dropper or initial execution stage. The ClamAV detection 'Xls.Dropper.EPPlus-9802867-2' further supports its role as a malicious dropper.

Heuristics 4

  • ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro

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) 852 bytes
SHA-256: 81f33300654310c197dae8afeca1601921264cd0c6899cee5ee40aa84ed99c28
Preview script
First 1,000 lines of the extracted script
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 = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
    Dim Program As String
    Dim TaskID As Double
    On Error Resume Next
    Program = "calc.exe"
    TaskID = Shell(Program, 1)
    If Err <> 0 Then    
        MsgBox "Can't start " & Program
    End If
End Sub

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 = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 4608 bytes
SHA-256: 44402c955071ab4b6f0d3548363fba9d579e2c1b675e54b1ee2e39aa9cfa143b
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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