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

Static analysis result for SHA-256 48bd8dbc9c457e8e…

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2020-11-12 12:36:01 Authoring application: Microsoft Excel
MD5: 532cbce1d7817fecec2630e6d53ce5a8 SHA-1: 547153200d78573914fd58bb75cf8fc02df5b723 SHA-256: 48bd8dbc9c457e8ebb476cc7dcf5cc03209584037bd6ef15410d4e5acb212828
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to perform a malicious action, likely downloading and executing a second-stage payload.

Heuristics 3

  • 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.
  • 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
9f0203657a7646edd5dd65c4bdf49ae86a376a9c9748b6b4b76ad47b4525be87		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 10061 bytes

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