Office (OOXML) / .XLSM malware analysis — malicious · cd85f3e23a5923fa

MALICIOUS

Office (OOXML) / .XLSM

30.6 KB Created: 2021-03-16 08:29:09 UTC Authoring application: 16.0300

MD5: 9e758d074b9df20b147d61e1adc2ba05 SHA-1: cc5778e2bed2cdd2fdb08a7f2095d913b945cd31 SHA-256: cd85f3e23a5923faa3f94ee3b59aee014ac37f9631a5570f2a5c65868d268058

88 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1059.001 PowerShell T1566.002 Spearphishing Attachment

The sample is an XLSM file containing Excel 4.0 macros, a known technique for executing malicious code. The presence of VBA macros and a hidden worksheet further indicates malicious intent. The macros likely download and execute a second-stage payload, though the specific URLs are benign schema references. The document body is heavily obfuscated and does not provide clear user-facing 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` `d15e850b0e3ba80973e1af068bcc8b60341282086d9d7550626d277c9cef34d0`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2509 bytes
`vbaProject_00.bin` `f817eb5de77bf218caf1dd21fbb6f71c498ea00c792f806d349616310af0b83e`	vba-project	OOXML VBA project: xl/vbaProject.bin	23040 bytes
`xlm_sheet_00.xml` `c77998eae21f87e28e77a0b0752a67d2a6486bd14af15ddec5704a6fbd8a0b74`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	815 bytes

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