Office (OLE) / .XLS malware analysis — malicious · b5e44195dd25a2d9

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-27 11:45:06 Authoring application: Microsoft Excel First seen: 2022-04-27

MD5: 7b4a9778108c6d56945d2f2aa12c3827 SHA-1: ba78d3bbaffe082646265afdc171efdac570eab9 SHA-256: b5e44195dd25a2d928b9497218c497368decf1d0cf6ae8832a35a2985e784271

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 (XLM) macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage payload. The document body contains obfuscated text, but the primary threat stems from the XLM macro 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` `2a3be810a3ff6498dc79e65ab6e6a958a5cb98b90e04e4bd075cdb853b7ffead`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	7016 bytes

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