Office (OOXML) / .XLSM malware analysis — malicious · 58f7f5541b61a1f0

MALICIOUS

Office (OOXML) / .XLSM

331.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300

MD5: 3ebbf38f7e0df5aa4bab03b543559c4f SHA-1: 5ee96aae5ef49ce6de6785e92c0a3c666a61c33a SHA-256: 58f7f5541b61a1f01d8c4aca2eb16b5efc8dc687c434097da534c51e8d689a16

250 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1204.002 Malicious File

This XLSM file contains multiple Excel 4.0 macro sheets, including an Auto_Open defined name, which is a common technique for executing malicious code upon opening. The macros utilize dangerous functions like FORMULA and REGISTER, indicating an intent to download and execute a second-stage payload. The ClamAV detection as 'Xls.Downloader.IcedID' further supports this assessment.

Heuristics 6

Excel 4.0 macro sheet (10 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.
Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME

Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
Dangerous XLM formula APIs: FORMULA, GOTO, REGISTER, HALT critical OOXML_XLM_DANGEROUS_FN

Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
ClamAV: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 10 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 — context-specific rules above attribute URLs they actually evaluated; this rule lists URLs that were present in the bytes but were not otherwise tied to a specific finding.
URL http://schemas.openxmlformats.org/spreadsheetml/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
- http://schemas.microsoft.com/office/spreadsheetml/2014/revision
- http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
- http://schemas.microsoft.com/office/excel/2006/main
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 10

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `f625217fb847b046d42bbedbfc768678a9ca133653762a5a97d60701302827dc`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3496 bytes
`xlm_sheet_01.xml` `05429996701eacd52396b49a7b542ebf5f54ec159e49392a0fde30360c280f6c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	2017 bytes
`xlm_sheet_02.xml` `c93414afa90d0aed96b0ce72668e15428c1af49ef990d4433b19efa6b27dd697`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2703 bytes
`xlm_sheet_03.xml` `caf907d21dc38a6bc75aedd846db9e62599779d4c2dbd3f24898f275d22c250a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1521 bytes
`xlm_sheet_04.xml` `7667966c8045cbbf1d7c1f279245a5e7c4ac004e5ebe30fbd872010d3792710f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1791 bytes
`xlm_sheet_05.xml` `c2e30072b0b55de845ae0cc0cf580b57d25538df7bd72d890703ffb59bd466f3`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1667 bytes
`xlm_sheet_06.xml` `4a0db02a3673bae10855faec06cd35685ff751631b0072a271b38d935beecf95`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1735 bytes
`xlm_sheet_07.xml` `a0c80460b9f4e41cc5c80274d1c193d030f8b4e954b0aa51ef669e0af14e35d8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1679 bytes
`xlm_sheet_08.xml` `1c52474b1448a0ffd9d21d1a06b05ada2668f4c15ffc52265026119f5dff69ca`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1611 bytes
`xlm_sheet_09.xml` `6dabbcd902efa205f4f62712457f79144c15a373fe7c951a3cc043bb5817e545`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1790 bytes

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