IcedID Office (OOXML) / .XLSM malware analysis — malicious · cde0f0a2eec45cfe

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: d3c4c560a7a9b2f76131c71097301744 SHA-1: 38df22be48ade97943d789874fbadfa7c98a6e0f SHA-256: cde0f0a2eec45cfeb561ee9c64b32e1c2839c67b63ab6eeb2aa0949ff81117f5

250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The critical heuristics indicate the use of dangerous functions like FORMULA and REGISTER, commonly employed to download and execute payloads. ClamAV detection confirms this as a downloader variant of IcedID, likely responsible for fetching and running a second-stage payload.

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` `96fef4185c719a422db4ff5116ec06951e8474b003a4456b635c16ca4c8aed1f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3864 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` `1a7af89e4cf7b3f73e9df27b77fe950621de8a90c0032239be05b21b75e5f301`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1801 bytes

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