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

Static analysis result for SHA-256 8ef4f92eeff604c0…

MALICIOUS

Office (OOXML) / .XLSM

578.2 KB Created: 2018-09-27 10:58:35 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2025-12-23
MD5: b572151155cdb30aa3c5096071720dbf SHA-1: cb22695d92994cd2cdee3aadd8304262f18495ea SHA-256: 8ef4f92eeff604c0dbd125cf358350141d9e3c1ef400775365b202c5d95b920e
258 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1566.002 Spearphishing with Attachment

The sample is an XLSM file containing obfuscated VBA macros, including a Workbook_Open auto-execution loader that uses CreateObject and Shell/exec functions. The document body presents a fake Goods and Services Tax (GST) reconciliation form, indicating a lure for financial information. While no direct payload execution URL was found, the presence of a VBA loader and the invoice lure strongly suggest a phishing or financial fraud attempt.

Heuristics 9

  • 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
  • External relationship high OOXML_EXTERNAL_REL
    External target in xl/externalLinks/_rels/externalLink2.xml.rels: file:///C:\Users\ashutosh.khaitan\Desktop\Worksheet in SRS_Offline_GSTR10_30052018.xls
  • 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
  • Hidden worksheet (veryHidden, hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 7 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://www.gst.gov.in/download/returns
    • 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
    • http://www.frez.co.uk
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://www.opensource.org/licenses/mit-license.php
    • http://code.google.com/p/vba-json/
    • 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
    • http://www.ietf.org/rfc/rfc4627.txt
    • https://support.microsoft.com/en-us/kb/272138
    • http://www.opensource.org/licenses/mit-license.php)�

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
d9181be68dd06a6480d64f9918d21cba95fabc95681839faa73ff05dd639f946		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 505088 bytes
vbaProject_00.bin
d3a215187ce24c813bdf50881880f66075e80288fa6650a81b8d68b383850033		 vba-project OOXML VBA project: xl/vbaProject.bin 769024 bytes

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