Office (OLE) / .XLSX malware analysis — malicious · a61806282ca67747

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-25 10:45:55 Authoring application: Microsoft Excel

MD5: e81296a150c7db5bf4111124738aa7e6 SHA-1: 6afa8ef293b04e787452d6b4090250035999a6cc SHA-256: a61806282ca67747a780593016e82397776f33b686e2b1ce8eaf20ca4a093c36

140 Risk Score

Malware Insights

MITRE ATT&CK

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open macro, which is flagged as critical due to the use of dangerous functions like RUN. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to execute arbitrary commands. The presence of the Auto_Open function indicates an attempt to automatically run malicious code upon opening the spreadsheet.

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` `85171bc0e01aa7af5fdd57ec2962b916de4403553538d102d6b690b892648554`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6461 bytes

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