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

Static analysis result for SHA-256 1131b55cf591f4ab…

MALICIOUS

Office (OLE) / .XLS

44.0 KB Created: 2008-04-01 09:49:34 Authoring application: Microsoft Excel
MD5: 1344a07d6f9ae79308f91fd643df528e SHA-1: e753b5a26970968a798dc4695170e7f7d25ce0cb SHA-256: 1131b55cf591f4abdf1b75fccf685a4966f5680b67cb6bf0291bb2235e687a7e
200 Risk Score

Malware Insights

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

The file contains critical heuristics indicating the presence of Excel 4.0 (XLM) macros, specifically an Auto_Open entry. This macro sheet utilizes dangerous formula APIs, including the RUN function, which is commonly used to execute arbitrary code or download further payloads. The presence of 'Poppy by VicodinES' and 'Narkotic Network' markers suggests a known legacy malware lineage.

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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
5b8766a0d4f1e016129ca5f8ccacf53cbef92fe0c52ca2747c8b129c14f4c7fc		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 19638 bytes

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