Office (OLE) / .XLSX malware analysis — malicious · 0715351e4a285f80

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:42:44 Authoring application: Microsoft Excel

MD5: 864acaf448772a84b9ebc94a004d34ba SHA-1: d865f029391de34790a5802aee8c7cac2c5d8fa4 SHA-256: 0715351e4a285f80907d9d2957dcf137408d3e47f94ef1fb5cfd375b3925d186

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating potential malicious execution. The presence of dangerous formula APIs like RUN further supports this. The macro sheet is likely designed to execute arbitrary code upon opening the spreadsheet, a common technique for initial execution.

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` `9a8f647314bd66edf534ea67f574f719ed70a3572199cdc72736bba0d5a02be3`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6386 bytes

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