Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a20040953daa7af9…

MALICIOUS

Office (OOXML)

383.7 KB Created: 2019-11-07 15:08:52 UTC Authoring application: Microsoft Excel 16.0300
MD5: b1af86e2a64b456cc15b85b76b680ab2 SHA-1: 0f6da08c10396610008bbeb7b900aab9ef4d1e98 SHA-256: a20040953daa7af9d72e7208084c2138d506ff26e9d7455f9d1a6dfa6af1cbdf
302 Risk Score

Malware Insights

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

The critical heuristic 'OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER' indicates an obfuscated auto-exec VBA loader that uses CreateObject and Shell functions. The Workbook_Open macro is present, suggesting execution upon opening the document. The script likely downloads and executes a second-stage payload from one of the embedded URLs, such as those related to quickfs.net, which are treated as IOCs.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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
  • 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://github.com/timhall/VBA-Dictionary
    • https://github.com/VBA-tools/VBA-Web
    • https://quickfs.net/profile
    • https://quickfs.net/account
    • https://quickfs.net/watchlist
    • https://quickfs.net/screener
    • https://quickfs.net/templates
    • https://quickfs.net/upgrade
    • https://quickfs.net/using-the-excel-add-in
    • https://api.quickfs.net/v2/tokens
    • https://beta.quickfs.net/beta
    • https://quickfs.net
    • https://api.example/com/v1/messages/123
    • http://www.outlookexchange.com/articles/toddwalker/BuiltInOLKIcons.asp
    • https://github.com/VBA-tools/VBA-Web/wiki/XML-Support-in-4.0
    • https://github.com/VBA-tools/VBA-Web/wiki/Url-Encoding
    • http://www.di-mgt.com.au/src/basMD5.bas.html
    • https://github.com/VBA-tools/VBA-JSON
    • http://www.vbaccelerator.com/home/VB/Code/Techniques/RunTime_Debug_Tracing/VB6_Tracer_Utility_zip_cStringBuilder_cls.asp
    • https://github.com/VBA-tools/VBA-JSON/pull/82
    • https://github.com/VBA-tools/VBA-UtcConverter
    • https://appletoolbox.com/2015/10/mouse-cursor-pointer-disappears-invisible-missing-fix/
    • https://github.com/VBA-tools/VBA-Webt
    • https://github.com/VBA-tools/VBA-Web/VBA-W�
    • https://quickfs.net/screener�
    • https://quickfs.net/using-the-excel-add-in�
    • https://github.com/VBA-tools/VBA-Web�
    • http://www.outlookexchange.com/articles/toddwalker/BuiltInOLKIcons.asp�
    • http://schemas.microsoft.com/office/2006/01/customui
    • http://schemas.microsoft.com/office/2009/07/customui
    • http://www.opensource.org/licenses/mit-license.php
    • http://msdn.microsoft.com/en-us/library/office/gg278481(v=office.15).aspx
    • https://www.example.com/api/
    • https://api.example.com/v1/messages
    • https://api.example.com/v1/users/id
    • https://api.example.com/v1/
    • https://msdn.microsoft.com/en-us/library/aa383770(VS.85).aspx
    • http://curl.haxx.se/libcurl/c/libcurl-errors.html
    • https://api.example.com/v1/messages/1
    • http://msdn.microsoft.com/en-us/library/windows/desktop/aa384059(v=vs.85).aspx
    • https://api.example.com/
    • https://api.example.com/messages
    • https://api.example.com/messages/123?a=1&b=2
    • https://tools.ietf.org/html/rfc6265
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms724421.aspx
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms724949.aspx
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms725485.aspx
    • http://support.microsoft.com/kb/269370
    • https://api.example.com/v1/peeple/{id
    • https://tools.ietf.org/html/rfc3986
    +13 more URL(s)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
e8f89288f0574b28121eb04a171c369749cd92f30ac9b6892ed9b802130a7ee0		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 446055 bytes
vbaProject_00.bin
fb1bbc725f65815da5d662e618d27d27dbb1454f42002d294a46cdfe4f405408		 vba-project OOXML VBA project: xl/vbaProject.bin 871936 bytes

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