Office (OOXML) / .XLSM malware analysis — malicious · dc6a60b3e34036ff

MALICIOUS

Office (OOXML) / .XLSM

30.4 KB Created: 2021-03-02 09:04:20 UTC Authoring application: Microsoft Excel 16.0300

MD5: 511e8b55bf83390403e4072289dc7bb5 SHA-1: c7b3aca0a6de2f58c2df50438add0f936d4e6e0c SHA-256: dc6a60b3e34036ff634a0cb836fbe878ea4d8f7b109958d5faaf72f00908141f

90 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The file is an XLSM document containing VBA macros and an Excel 4.0 macro sheet, indicating a macro-based execution attack. The VBA code appears to be obfuscated, but the presence of Excel 4.0 macros (xlm_sheet_00.xml) is a strong indicator of malicious intent, often used to download and execute further stages. The heuristics confirm the presence of VBA and Excel 4.0 macros, and a hidden sheet, commonly used to conceal malicious content.

Heuristics 4

Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEET

Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 2 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
- http://schemas.microsoft.com/office/excel/2006/main
- http://schemas.openxmlformats.org/officeDocument/2006/relationships
- http://schemas.openxmlformats.org/markup-compatibility/2006
- http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `3942f1b7912f38fe8ec4385d56db234fa88f9c56843e1a175049c79e25eaf6c6`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2381 bytes
`vbaProject_00.bin` `4d5b7f775ba3b0402233f25969b9927e3b2714449ba93bf0c0a4dc52285e69e0`	vba-project	OOXML VBA project: xl/vbaProject.bin	25088 bytes
`xlm_sheet_00.xml` `6a391656549201c887614cde60218159fa7da164fd87c00b12dd24200c865d3e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	865 bytes

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