Office (OLE) / .XLSX malware analysis — malicious · 566febf5d3d89e8c

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:43:38 Authoring application: Microsoft Excel

MD5: b17ffd413a8e1e9d480bd6a2fecb8d14 SHA-1: ee909327a6d95afab142cb11659d7fc2e4864f5c SHA-256: 566febf5d3d89e8c7c2fc6ec3f9d134c62e0aec5752de945a7b9000010fc073b

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the XLM macro, suggesting it is designed to run arbitrary commands. The macro sheet itself is likely responsible for the initial execution of these commands.

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.

Filename	Kind	Source	Size
`xlm_macros.txt` `172a6436594ecc376a163cb488a2f46007c8b6235fab15a57a912ef7621b278c`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6539 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.