Office (OLE) / .XLS malware analysis — malicious · b67c9bb045030586

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2020-11-12 12:29:54 Authoring application: Microsoft Excel

MD5: 71661ec4904100765fa8173bd58cd3f8 SHA-1: 03224cc3af2b8d7f174c9212cf9a98d08e2413eb SHA-256: b67c9bb045030586563d3cc4e2d00d3e8e13bf8766be54a227164da1cfbc8669

140 Risk Score

Malware Insights

MITRE ATT&CK

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

The file is an Excel 4.0 macro sheet containing an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of the 'RUN' function within the XLM macro suggests that the macro is designed to execute arbitrary commands, likely for downloading and executing a secondary payload. The document body contains heavily obfuscated and unreadable text, providing no direct clues about the lure.

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` `25068709c0ad07a7368e3e4fdfe8016eaacda31e65e56a3c08f5e1797a3d8c44`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	10083 bytes

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