IcedID — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 f31d67acf9ea5121…

MALICIOUS

Office (OOXML) / .XLSM

170.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 6285bd5f439f13fbbeb3368f2d36a8af SHA-1: 5af77d6af06a263da5fee39155a4a5b50625745b SHA-256: f31d67acf9ea5121b7d77c85c1fa816604f26c82bb5c1eb5c527abf2d047c2e5
240 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, specifically utilizing the Auto_Open function and dangerous API calls like FORMULA.FILL, GOTO, RETURN, and EXEC. These functions are indicative of a downloader, designed to fetch and execute a secondary payload from external sources. The ClamAV detection as 'Xls.Downloader.IcedID' strongly suggests the IcedID banking trojan family. The embedded URLs are likely the initial points of contact for the payload download.

Heuristics 5

  • Excel 4.0 macro sheet (2 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, GOTO, RETURN, EXEC 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
    • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
21b43b24fc2a4b371e0eab7f7cbec4533426891fb10a2e0ff24cac569d7b0f37		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5565 bytes
xlm_sheet_01.xml
5c4423f87de4646755545b93c22f66e76828f61098e22de81e80e42a48f190a9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2434 bytes

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