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

Static analysis result for SHA-256 d222b7c58c423454…

MALICIOUS

Office (OLE) / .XLS

42.0 KB Created: 2020-11-13 16:16:46 Authoring application: Microsoft Excel
MD5: 4bd15ce4f41e2061d25369fe2c717089 SHA-1: a6eda2a39a4bcc7083d64697085644c03d059a87 SHA-256: d222b7c58c423454d78704151a296c885c1c024b2cadf69e05bad7ffbe20660e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell 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 strongly suggests the macro is designed to execute arbitrary commands upon opening, likely to download and execute a second-stage payload. No specific IOCs were extracted, but the technique is indicative of a downloader or initial access stage.

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
7124db2b90086b3280df24c6e99734a37442c45a51c4f1c38cc2d7c174ebfca0
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9702 bytes