IcedID Office (OOXML) malware analysis — malicious · bbd1472629b67908

MALICIOUS

Office (OOXML)

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

MD5: 42ff906b01b870825d8994fd009b82fa SHA-1: 39bd006986c3f543f889e472287f2bbc140634ff SHA-256: bbd1472629b67908fa9a7515fd8c655bdd71cc864d22fd5de5a52f6e0dd894ab

250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

This Excel file contains multiple Excel 4.0 macro sheets, including one with an Auto_Open defined name, which is a common technique for executing malicious code upon opening. The critical heuristic 'OOXML_XLM_DANGEROUS_FN' indicates the use of dangerous XLM formula APIs like FORMULA and GOTO, which can be used to download and execute payloads. ClamAV detection confirms this as a downloader for the IcedID family.

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, 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 — 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
- 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/spreadsheetml/2016/revision6

Extracted artifacts 10

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` `d426f8d1ffb9f4cae0b3596b59264854211f5a37409aff811f2b6e3d0b4471fc`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1743 bytes
`xlm_sheet_03.xml` `722e5d05ff76efbc613cfc8faf6010a45d36bce5b42c805efd4dad491ab57285`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1585 bytes
`xlm_sheet_04.xml` `bbabdb72f964374a773f09d55c2ef66fa57494857b47c84f6883880468c3e05f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1795 bytes
`xlm_sheet_05.xml` `ee656362086a167f40427380169b904c4e8f6d7223dba3711b5f2ca8ecae3067`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1879 bytes
`xlm_sheet_06.xml` `2166c7457651893fa9459576c7b181df82d76c4fcebd021c0c20c24dedc93e62`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet10.xml	1920 bytes
`xlm_sheet_07.xml` `d336d714c064b1de9e9a56ccd73ade8b1f0edff76c17a7e66d685ef714ea6d20`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet11.xml	1929 bytes
`xlm_sheet_08.xml` `aac2ffcbbae09ab4b5869d56560bc65d237d62e10fc10d91608ce8e2b370ca9d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet12.xml	2195 bytes
`xlm_sheet_09.xml` `f132f4041e583271c3d5f2834d2cb24dbe90419bc9d67396179c90ec86cd5770`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1442 bytes

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