Office (OOXML) / .XLSM malware analysis — malicious · a00d1d5e58241874

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: b0f2dcd95efaaff4a848e5e22f9604f1 SHA-1: a586b13a51bc230365043b521c9a17074ad7832f SHA-256: a00d1d5e58241874d09ab383a957562d9f55038656feb477223b1ee08d79af01

250 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1204.002 Malicious File

This XLSM file contains Excel 4.0 macros, indicated by multiple heuristic firings including the use of dangerous functions like FORMULA, RUN, and GOTO. These functions are commonly used to download and execute arbitrary code. The ClamAV detection as 'Xls.Downloader.IcedID' further supports its malicious nature as a downloader. No specific URLs were extracted, but the mechanism strongly suggests a payload delivery attempt.

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, RUN, HALT, GOTO 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 16 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` `bfd73345784cbd4b12801aaf913d8b3fc6c2f1febe907c79661534aef36889f1`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3134 bytes
`xlm_sheet_01.xml` `7c07ec4feb00a9caf0753d573dcca60ccdbca0e0508331bc6d2646dad1bb2e33`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1773 bytes
`xlm_sheet_02.xml` `a065e3b7d289f8c3d55db4c228b49b4806c3a43892aa49fc336d401d0c66228a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2309 bytes
`xlm_sheet_03.xml` `e5386217441be9318be875b68c4d2a3c61931493a08b253b17886aa7524008c2`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1420 bytes
`xlm_sheet_04.xml` `8f5efe33bb7fbe9e6a0021b9fd00a9f20c83cca799d0a6556ab9e3c793858141`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1485 bytes
`xlm_sheet_05.xml` `12ccf75d221540d08c66df9c30690d6e80c0a29001dca548947cebda1e4b698f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1423 bytes
`xlm_sheet_06.xml` `c679579238a1c7233936755b04ff18098c930f046a14ab1fff60b09748317fb8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1422 bytes
`xlm_sheet_07.xml` `5b459e14f7d6aa8922cba85b05056a0ff5a98a366bcd460248941cdf5c28fb65`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1424 bytes
`xlm_sheet_08.xml` `b26c49c44be09583f4fa8e8590fedb6c70209dbc98dc541fb4c3cba0a675ae91`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1421 bytes
`xlm_sheet_09.xml` `5325d69ce57334b77e265dd8e650f68c32cee06fb4562c075fa04f98d44e138d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1350 bytes

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