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

Static analysis result for SHA-256 c8f7575c4cb55522…

MALICIOUS

Office (OLE) / .XLS

92.5 KB Created: 2009-10-29 00:57:02 Authoring application: Microsoft Excel
MD5: d712c17da3d819be121e1a3f6ed5bf8c SHA-1: 6420e56352cc573e14021468edd29e01abc4f831 SHA-256: c8f7575c4cb555225bd17920cc2eb9f5e6bd267228e8bc379c2e77f724deae4d
200 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros, specifically an Auto_Open macro. The macro sheet is identified as 'XL4Poppy' and contains references to 'Classic.Poppy by VicodinES' and 'The Narkotic Network 1998', suggesting it's a known macro virus. The presence of 'RUN' and other dangerous formula APIs in the Auto_Open macro indicates it's designed to execute arbitrary commands or actions when the workbook is opened. The document body text, while containing what appears to be Vietnamese real estate-related content, also includes references to 'Book1.xls' and infection routines, reinforcing the malicious nature.

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
4832b01f3ad9e9a4bf35bbb3ab6668cfb4f072f9b019edd9132c30a1eba07d99		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 14581 bytes

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