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

Static analysis result for SHA-256 b1a153a9c2e1364d…

MALICIOUS

Office (OLE) / .XLS

77.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: fae9edf34070ef49df9d96982eba54e2 SHA-1: 32f2f090cfd97c388a6e57a622c5f415c4a22cf3 SHA-256: b1a153a9c2e1364d8d9976768c0c48e40b2f84f543c6f7794eb843e60654dbc2
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1547.001 Registry Run Keys / Startup Folder

The file contains legacy Excel 4.0 (XLM) macros, specifically an Auto_Open entry, which is a strong indicator of a macro virus. The heuristics indicate the presence of a known macro virus marker ('Poppy by VicodinES', 'Narkotic Network'). The document body and script fragments confirm the intent to infect other workbooks and save them as 'Book1.xls', suggesting a self-propagating mechanism. The specific functions identified (RUN) suggest it may also execute arbitrary code.

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
f1ebe6a040a753f67c6b864d6230aa096817ac2e1c50c792e9f08a671b0e41e0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 10274 bytes

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