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

Static analysis result for SHA-256 26f18be61a20942c…

MALICIOUS

Office (OLE) / .XLSX

23.5 KB Created: 2001-06-20 07:50:36 Authoring application: Microsoft Excel
MD5: 4fd6f23d588ab0192c34735139d88677 SHA-1: 153a2f0aae1c0b78c332957169a78221cd453e24 SHA-256: 26f18be61a20942c4e189797388543047b30e08893cbb524c2d71c510e59607b
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 known technique for executing malicious code upon opening the workbook. Heuristics indicate the use of dangerous formula APIs like RUN, suggesting the macro attempts to execute commands or load other payloads. The presence of strings like 'Poppy by VicodinES' and 'The Narkotic Network 1998' within the document body and macro comments points to a known legacy Excel macro virus. The macro also appears to attempt to infect other workbooks and save them as 'Book1.xls', indicating a propagation mechanism.

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
8527425e0f656b4e8e0ab94fb8797dc57fe95420a75d909da8c4a54da74c8d40		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9124 bytes

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