Office (OLE) / .XLSX malware analysis — malicious · f4663339e09f5753

MALICIOUS

Office (OLE) / .XLSX

27.0 KB Created: 2020-11-05 03:18:54 Authoring application: Microsoft Excel

MD5: 25873330143e2bc2b9b03a8bf3a527ce SHA-1: 945a113f72ce87814a46f47e6e7290ba00577a22 SHA-256: f4663339e09f575301700439ee6afbba8b6193a789fd5bb5bf96a966f746a7d6

160 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1566.002 Spearphishing Attachment

This Excel 4.0 macro-enabled workbook contains an Auto_Open macro that executes a PowerShell command. The command 'powershell.exe -ex bypass -nop -w 1 iex' is indicative of a downloader or initial execution stage, likely intended to fetch and run a second-stage payload. The presence of Excel 4.0 macros and the specific PowerShell execution pattern strongly suggest a malicious intent, commonly seen in macro-based malware delivery.

Heuristics 4

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.
Reference to PowerShell high SC_STR_POWERSHELL

Reference to PowerShell
LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND

Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
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` `176cb93610b9abc573d242e42df86ece1bc22f593f60841d9bb8ab270bafa245`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	1388 bytes

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