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

Static analysis result for SHA-256 efaca0d564217bf6…

MALICIOUS

Office (OLE) / .XLSX

109.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: f017a5e5ca7ce1deadafb8f7309f4136 SHA-1: 63326391f928a2b15b80b0562ba13502f68353c7 SHA-256: efaca0d564217bf6476812ea58d91d02950b1830db155a6c3ecec4143cdbcb2e
142 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, which is a strong indicator of malicious intent. The macros reconstruct and attempt to download payloads from five different URLs. The reconstructed URLs are: "http://arzulens.com/wp-includes/7gySgTg/", "https://simplinteriors.com/wp-admin/B1e/", "https://www.swaong.com/wp-admin/k9Db4Vjafnk/", "http://68bets.site/b/bL2bq71qNY/", and "https://farocfc.com/wp-admin/rX9FcCxf0Cf4bj/". These URLs are likely used to fetch and execute a second-stage payload.

Heuristics 4

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • URL reconstructed from XLM cell array (5 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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://arzulens.com/wp-includes/7gySgTg/
    • https://simplinteriors.com/wp-admin/B1e/
    • https://www.swaong.com/wp-admin/k9Db4Vjafnk/
    • http://68bets.site/b/bL2bq71qNY/
    • https://farocf.com/wp-admin/rX9FcCxf0Cf4bj/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
048fc7adf1ec2dc53854adf0fab11898e6ff015a9a500734b3c71fb4ace1ee2a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1514 bytes

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