Office (OOXML) / .XLSM malware analysis — malicious · e104c204c8757b65

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 17ca43c41202c41c6abae6e0e7b6ba91 SHA-1: 1657072df63d06f4ded461be21dfb037e51b8055 SHA-256: e104c204c8757b65dcebdbd5f8c480b90fe131339f1bae0a87b61f479a49c2c3

242 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell T1105 Ingress Tool Transfer

The file is an XLSM document containing Excel 4.0 macros, which is a known vector for malware delivery. The macros utilize dangerous functions like FORMULA.FILL, which can be used to download and execute arbitrary code. The ClamAV detection as 'Xls.Downloader.IcedID' further supports its malicious nature as a downloader. The specific IOCs are URLs extracted from the document, though they appear to be schema-related and not direct download links.

Heuristics 5

Excel 4.0 macro sheet (3 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.FILL 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
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

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `4579e9d9134ee88a7a896edfcabc863e2e82e557af728eaf391ae4946f07af34`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	1288 bytes
`xlm_sheet_01.xml` `0101ee9e8c3951ec575bb7566d5eddf13ee538f0fe9782373a93f2413e5887d6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	1067 bytes
`xlm_sheet_02.xml` `3f1fe57153abf51373b41e259e14cd7b677ecfec1f43f73b973ae63b3ad3f3c1`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1332 bytes

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