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

Static analysis result for SHA-256 a4572041d73e57af…

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 11:40:11 Authoring application: Microsoft Excel
MD5: 8c39a8f55aa8c8f512f07f8664f736a7 SHA-1: 0d476001e8a86a5a72b02a835e0e0d1a82ef44e0 SHA-256: a4572041d73e57af0fe46a27ddc132042e50555b7e45efb34c37fdc7218784b4
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro sheet is designed to execute automatically upon opening the workbook. The presence of 'RUN=0' in the heuristic firing suggests the macro is capable of executing arbitrary commands. While no specific URLs or hashes were extracted, the primary function appears to be the execution of a malicious command, likely for payload delivery.

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
58833c9e8e8e3d43d053e1b3fc545c15fd054007d0e2a5e6658d1ba5112d0a2f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6800 bytes