Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 28d9e64e471cf8e9…

MALICIOUS

Office (OOXML)

17.2 KB Created: 2021-02-26 10:57:37 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-06-20
MD5: 67a388373feebf5cf6f66a0db9bfd570 SHA-1: 23fc075e0113e8b06aabe97e11b603afe73fc44e SHA-256: 28d9e64e471cf8e9a7ccbf0947f65d9e02c1bc477a761cc67b2f0ce045ce2b6f
168 Risk Score

Heuristics 5

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    cmdResult = Shell("cmd.exe /k " & strPath, vbNormalFocus)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set fso = CreateObject("Scripting.FileSystemObject")
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
    Matched line in script
    cmdResult = Shell("cmd.exe /k " & strPath, vbNormalFocus)
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()

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) 1761 bytes
SHA-256: f83768e7f1d6b64c3c8a3e4cd98c63aa4de76a56caeb6a2aa173d1ad1a5321da
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
Sub Workbook_Open()

' This is the virus (test!!!)
Dim EicarVirusString As String
Dim EicarPart1 As String
Dim EicarPart2 As String

' Very rudementary obfuscation
EicarPart1 = "X5O!P%@AP[4\PZX54(P^)7CC)7}$EICA"
EicarPart2 = "R-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*"

EicarVirusString = EicarPart1 & EicarPart2

' Create some filesystem objects
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")

' Get TEMP folder location
TempFolder = fso.GetSpecialFolder(2)

' Create the file
strPath = TempFolder & "\eicar.com"
Dim oFile As Object
Set oFile = fso.CreateTextFile(strPath)

' Write the payload
oFile.Write EicarVirusString

' Close and cleanup
oFile.Close
Set fso = Nothing
Set oFile = Nothing

' Show warning
result = MsgBox("Hello, I have just created a test virus in your temp directory (" & strPath & "), and am about to run it. Just click OK and enjoy. You shoud either see a text message stating that EICAR has run, or (and that is intended) it should be deleted by your virus scanner.", vbCritical, "Test Virus Saved")
cmdResult = Shell("cmd.exe /k " & strPath, vbNormalFocus)


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 = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 11776 bytes
SHA-256: 67b7b0066ade181757f8bc058fd18767e31af15d8c3320220464f93d751db429

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