Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 642522a9ad3eebb3…

MALICIOUS

Office (OOXML) / .XLSX

154.2 KB Created: 2021-04-26 10:52:43 UTC Authoring application: Microsoft Excel 15.0300
MD5: ee49601b2ca5bb7ee29aa48c3c8a60cc SHA-1: faa83df8f90adb7c5cd714e41ea29ff507b677ed SHA-256: 642522a9ad3eebb378e85e7abd5c68489cd1d727fc7548224c9c81fe69347198
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1566.001 Spearphishing Attachment

The sample is an Excel document containing obfuscated VBA macros designed to execute automatically upon opening. The Workbook_Open macro utilizes CreateObject to download a second-stage payload from one of the listed URLs and execute it. This behavior is indicative of a downloader or initial access stage for further malicious activity.

Heuristics 8

  • 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.
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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 https://demo.mywildcard.in/o4xXaUzJ8QqW0.php
    • https://vancouverwebhosting.net/images/0T81Lvi9WmK.php
    • https://phonecases.sydney/jamaicapropertyfinder.com/wp-includes/SimplePie/XML/Declaration/oAr7ngk9.php
    • https://seguridadbue.com.ar/wp-content/themes/twentyseventeen/template-parts/footer/Wzaj2N2PxIw.php
    • https://greymattermedia.co.za/images/cAGeJH4IUGyb.php
    • https://ehostpro.xyz/client/templates/orderforms/universal_slider/css/2g1y7XgQv43EN.php
    • https://showromance.com/wp-content/plugins/updraftplus/templates/wp-admin/AqN0htF0m472.php
    • https://tojaco.co.uk/doj6dErUbir.php
    • https://driverschoice.sg/wp-includes/sodium_compat/src/Core32/ChaCha20/bFLA7icV.php
    • https://prothomsangbad24.com/wp-includes/js/tinymce/plugins/charmap/Aka3z22Go3.php

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
4f8385972c55018f792c5690677cdde9e508993a1377777db58144b7a26d9d02		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 10689 bytes
vbaProject_00.bin
2a4018e0574646dbb00f423a02ba4acdf0c1f58d102586d41fd4933e6842dc49		 vba-project OOXML VBA project: xl/vbaProject.bin 56320 bytes

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