Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8b1ad10c558f92e6…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:07 Authoring application: Microsoft Excel
MD5: 604e1a98f07ad857ec1cbcf4ddf073f7 SHA-1: be078f4d1eee8fac545c8787e689f06804948535 SHA-256: 8b1ad10c558f92e61bd7f856245b47f59b3abbd336d3a614e92d6ce0a34817b5
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name and dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute arbitrary commands upon opening the workbook. While no specific URLs or hashes were extracted, the presence of the Auto_Open function points to a downloader or initial execution stage for a malicious 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
484e8cf54daf5630cdbeedf0ffaa60ee781ecb5043ac697e52d34f1bca28e4c7
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6602 bytes