Office (OLE) / .XLSX malware analysis — malicious · e356073193e755b8

MALICIOUS

Office (OLE) / .XLSX

42.0 KB Created: 2020-09-28 00:53:43 Authoring application: Microsoft Excel

MD5: 56102dd3f0332324ae1b6acbbf59b698 SHA-1: 30f1522f52be4a87332ec015ef5acd51ddbceb18 SHA-256: e356073193e755b8d35274e947d10f51e2a72ec2c8e90bc6ad463bea33cd1aa4

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The macro sheet contains references to dangerous functions such as RUN, suggesting it is designed to download and execute a second-stage payload. No specific family could be identified, but the technique is consistent with macro-based malware 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.

Filename	Kind	Source	Size
`xlm_macros.txt` `70de7c8ca7a8f0ec01ce49a8e2f1913c8423e547d565e3454a59cfdb57a1929e`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	8162 bytes

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