IcedID Office (OOXML) / .XLSM malware analysis — malicious · 77996e15c4943bb2

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 914cd41e0828cb1fd618063110524af5 SHA-1: da7eec4cb7821386594aee09ea16a3da891028e6 SHA-256: 77996e15c4943bb27dce0c859f911546d1649602a83d565f6b310fd99575563e

250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file is an XLSM document containing multiple Excel 4.0 macro sheets. Critical heuristics indicate the use of dangerous XLM functions like FORMULA, GOTO, REGISTER, and HALT, which are used to download and execute payloads. The macros appear to construct a command to download a file from a list of IP addresses and execute it using 'rundll32'. The ClamAV detection explicitly names 'Xls.Downloader.IcedID'.

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 — 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` `080bf0d1913eabdbe68c9f55d92e797adb72f1bc1d886b19764eaaf321e40bcc`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3139 bytes
`xlm_sheet_01.xml` `05164b9cb70e0037b39b203885ebd44decd4d50bf6d78fd17a97030d1a30d169`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1775 bytes
`xlm_sheet_02.xml` `57964786069256c3cde5b674c74c83e32c7950a5a81fb86406607b9295962e79`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2200 bytes
`xlm_sheet_03.xml` `8e54ca9c8231ff6eeb2f34ba5a3783f05811c03293e81c3321c593743fc7d49b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1453 bytes
`xlm_sheet_04.xml` `bc63d00a02951125a391dfed946345cbbd3e47d5e732e1f67ca4c1232e853427`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1453 bytes
`xlm_sheet_05.xml` `1da17f060335fdb67c88a8c48e73de301d69d9af4b69c610a8ce665eeb86cad7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1452 bytes
`xlm_sheet_06.xml` `f6b4423280cd454553d841491284df3eff350a07bc739b9add3542ffb6a9432a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1454 bytes
`xlm_sheet_07.xml` `bdf4c4c111e091debcc20b38007edacf914de0a9b4c13576faa0148f2eae61a7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1455 bytes
`xlm_sheet_08.xml` `a6ea880b09fb36b15b9b86dc98d863447933c1968cf6c7d3bec7927472189efa`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1451 bytes
`xlm_sheet_09.xml` `6b415b149f32e6deb26c4b2856c7977501b27603cf485b4daf15fd4fee7940d5`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1496 bytes

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