IcedID Office (OOXML) / .XLSM malware analysis — malicious · 2d362c4b0bdfac62

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: fc4b2ef7abf720d2e55cec08115e052f SHA-1: 35b9a73cbb58bafa5517e4c0c8b04156efa99a59 SHA-256: 2d362c4b0bdfac6266aec727b76a2804072fabec4e108a1186d06c6f06b0c9bf

250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File

The sample is an XLSM file containing multiple Excel 4.0 macro sheets, including an Auto_Open defined name. Critical heuristics indicate the use of dangerous XLM formula APIs like FORMULA, GOTO, and HALT, which are commonly used to download and execute payloads. ClamAV detection explicitly identifies the file as 'Xls.Downloader.IcedID', confirming its malicious nature and likely family.

Heuristics 6

Excel 4.0 macro sheet (14 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, 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 14 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 14

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `83dba5bfbe15006ac89e8f80dd7cef1659412a3734905e1c32eb8daf6ea654c1`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	1380 bytes
`xlm_sheet_01.xml` `c82a3f1a5a07e2c3dfdeeb07a65d6c60c5bde7fafc322a698567c77157ce96d2`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1616 bytes
`xlm_sheet_02.xml` `2d666c0156d5379ae66f25c08b3a2af99682820e2f3d34113e67d10adba7eb62`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2222 bytes
`xlm_sheet_03.xml` `718618d657190573a85de16f29f95f961a6d033973a622ac95381fd8c6bda9d7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	3859 bytes
`xlm_sheet_04.xml` `18ffdb2b8fdccdea02e96c749f85a50785a70e432f304017fb5424282e69883f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	2313 bytes
`xlm_sheet_05.xml` `d426f8d1ffb9f4cae0b3596b59264854211f5a37409aff811f2b6e3d0b4471fc`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1743 bytes
`xlm_sheet_06.xml` `7c938a7bb5e1d49c23f50c7382eb8d69094ccdb58d4425ca8ed1a35098f12ad9`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1740 bytes
`xlm_sheet_07.xml` `722e5d05ff76efbc613cfc8faf6010a45d36bce5b42c805efd4dad491ab57285`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1585 bytes
`xlm_sheet_08.xml` `bbabdb72f964374a773f09d55c2ef66fa57494857b47c84f6883880468c3e05f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1795 bytes
`xlm_sheet_09.xml` `ee656362086a167f40427380169b904c4e8f6d7223dba3711b5f2ca8ecae3067`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1879 bytes
`xlm_sheet_10.xml` `2166c7457651893fa9459576c7b181df82d76c4fcebd021c0c20c24dedc93e62`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet10.xml	1920 bytes
`xlm_sheet_11.xml` `d336d714c064b1de9e9a56ccd73ade8b1f0edff76c17a7e66d685ef714ea6d20`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet11.xml	1929 bytes
`xlm_sheet_12.xml` `aac2ffcbbae09ab4b5869d56560bc65d237d62e10fc10d91608ce8e2b370ca9d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet12.xml	2195 bytes
`xlm_sheet_13.xml` `f132f4041e583271c3d5f2834d2cb24dbe90419bc9d67396179c90ec86cd5770`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1442 bytes

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