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

Static analysis result for SHA-256 45febe070713a8c5…

MALICIOUS

Office (OLE) / .XLS

685.0 KB Created: 2020-11-24 00:41:25 Authoring application: Microsoft Excel
MD5: 7facca44e3c764b946cb370de32168bd SHA-1: a6518c8f99dd27a4c66afb0d6d2b9b822964d64a SHA-256: 45febe070713a8c5f7c5f8d53dad6c6c42fb20cc3d48f73fcb91e1a7fdf118d7
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary commands upon opening the file, likely to download and execute a second-stage payload. The specific command executed is not fully recoverable from the provided output, but the presence of 'RUN' as a dangerous function is a strong indicator.

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
a43668f9fa78bd7f4bbc557d462968b192c449c4efd82ac916cb739bf1924168
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 14170 bytes