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

Static analysis result for SHA-256 c35c5b5514c98f99…

MALICIOUS

Office (OLE) / .XLS

156.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 5f87d67abb06480d970a9c35d5707990 SHA-1: ea219ad2bf03c3afb33780b9ad0156e1a9329c07 SHA-256: c35c5b5514c98f995ff4c75fd132f4e609ded900d1272863be8fc3b010209f07
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information

The file is an Excel 4.0 (XLM) macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The macro sheet contains references to 'Poppy' and 'Narkotic Network', suggesting it's a variant of a known legacy Excel macro virus. The macro's purpose is likely to download and execute a second-stage payload, as indicated by the use of dangerous formula APIs like RUN.

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
0064ace5dac98c6d25b650ed03f774ed4a7f1a22acd9327304b28de08a03aa28		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 100162 bytes

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