IcedID Office (OOXML) / .XLSM malware analysis — malicious · 72da5a8ba62bc25d

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 245c3e542030fb5f37cc1786c6d2ad52 SHA-1: d3659467af26b5cf1773b69bd6b9820b1b777dcb SHA-256: 72da5a8ba62bc25dfbe12f189664117f79db3fcf2d539e3b1f8abc3923e8a2ea

250 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

This Excel macro-enabled document (XLSM) utilizes Excel 4.0 macros, specifically the dangerous FORMULA and GOTO functions, to download and execute a second-stage payload. The macro attempts to download files named 'Post.storg', 'Post.storg1', and 'Post.storg2' using 'regsvr32 -s' which indicates a downloader functionality. The ClamAV detection of 'Xls.Downloader.IcedID' further supports this assessment.

Heuristics 6

Excel 4.0 macro sheet (11 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 11 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 11

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `f50d0e58ff4b3bbf8f66fb8c7392258f65ea4187c2a029c0b32b4b4e8af9d5a7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	1544 bytes
`xlm_sheet_01.xml` `69bb1586fe51ef1446986f717fd1404e6248a5409450ce12060ebf3e6cf4bfed`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	3610 bytes
`xlm_sheet_02.xml` `edd56ce6c1aaebd6a961f4f3e21381f159f4e4a5cb9588dee71059686a23fd36`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	1813 bytes
`xlm_sheet_03.xml` `0bdab39d1e6e240b262fdb455004f95b6e641cefcb55184597b0791e3477830d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	2282 bytes
`xlm_sheet_04.xml` `1689f80fcd8d29bbe3f6826c85a4540f840aaca57f1dab7118361be453f9c62f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1457 bytes
`xlm_sheet_05.xml` `592faf795ef32e9abd34df5439e415f27d5e1c3900f372036296e9849f1da2dc`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1523 bytes
`xlm_sheet_06.xml` `21036e671bd96742131b768b836f683650b1b62627606efe875f8c786e301918`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1461 bytes
`xlm_sheet_07.xml` `8d2ada19e3ea28284efe269aede03d58a72dd70f04cc971c83273e788cc6af87`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1457 bytes
`xlm_sheet_08.xml` `938cc835b7ab4aa3dea37f0e63091f7a34f0b4608d7bd063ec89076fac32ce5c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1458 bytes
`xlm_sheet_09.xml` `3394a1195cc4e485811eb02b87115bd3b5f3f1bfb26f05d95729273c23b5e0a9`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet10.xml	1448 bytes
`xlm_sheet_10.xml` `769a8916d3134cc00e18e05c8b172dd3ba49607c493e21d1ff7faf8cc2427d28`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1370 bytes

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