Office (OOXML) / .XLSM malware analysis — malicious · 5655a3980b2a78f8

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 50fe611568c162c22b9f090ce7ca57f7 SHA-1: edd55574e8e5262f91104f59c21cdcde7e410a81 SHA-256: 5655a3980b2a78f802e41cfbcd41d0b608b51c4ac165c590911bd835d6469159

250 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an XLSM file containing multiple Excel 4.0 macro sheets. Critical heuristics indicate the use of dangerous XLM formula APIs like FORMULA, RUN, and GOTO, which are commonly used to download and execute payloads. The ClamAV detection as 'Xls.Downloader.IcedID' further supports this. No document body text was available for analysis, and no scripts were extracted.

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` `573abe2fe35b83cc816d5d113e03910c2cf04454401aa87f11b633f232a192e4`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3130 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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