Office (OLE) / .XLSX malware analysis — malicious · d420271e2beadbfc

MALICIOUS

Office (OLE) / .XLSX

37.0 KB Created: 2020-11-27 11:46:24 Authoring application: Microsoft Excel

MD5: 034d07951a04b69199e4407ff23e0710 SHA-1: e0a80aab1c0e2fcb6270d1e319cb025104675d9d SHA-256: d420271e2beadbfce6ec9dee0486073b5aaf573981cdc7546af885a59d670637

140 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding. The presence of the 'RUN=0' formula API indicates the macro is capable of executing arbitrary commands. This strongly suggests the file is designed to download and execute a secondary payload upon opening. No specific family could be identified, but the technique is common for initial access.

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` `92e333c1e0014041410f2315714b79b72f80e831335f3f2bcede770e07ae539d`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6804 bytes

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