Office (OOXML) / .XLSM malware analysis — malicious · f84d65ddf6a721ee

MALICIOUS

Office (OOXML) / .XLSM

82.8 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300

MD5: 100123b7843ed81d9973bd2f9705016d SHA-1: 1e032bb6d85dd83b41a9489a60fda1675145a7ab SHA-256: f84d65ddf6a721ee4343db90c97dc1e12b8cf79677bd2d9ddc9a703903a4271b

190 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an XLSM file containing multiple Excel 4.0 macro sheets. Critical heuristics indicate the use of dangerous XLM functions like FORMULA and HALT, which are often used to download and execute payloads. The presence of an embedded URL pointing to a DLL file further supports this, suggesting the macro's purpose is to fetch and run a second-stage malicious binary.

Heuristics 5

Excel 4.0 macro sheet (6 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, 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.
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 7 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://185.180.199.126/d1.dll
- 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 6

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `193229ba9fc998217c8f5403be5335e7947fb47fc0da8f87617ff8fec50c819a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	1382 bytes
`xlm_sheet_01.xml` `f80410d21d8afda8dc8102e0c6ffc0414f3e22dff3705f46503b6705ecdde7e6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1409 bytes
`xlm_sheet_02.xml` `3e8d916a4291837b0f0130c22045fb1b598a7b94685b3b146b8fa4a678a97974`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	1402 bytes
`xlm_sheet_03.xml` `17430653878ebd9f7a64babd78e34454ec405a79755466f199ed7bb8ec86ca01`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1523 bytes
`xlm_sheet_04.xml` `097c4fa99bbd0832fec019bf6fd313f35dd35257f6e9f120fb6698ff772ac964`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1416 bytes
`xlm_sheet_05.xml` `c851caa32c8b66dec7c2054ab22d3267c9c236d74b92e247ef2702a18eedd86b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1300 bytes

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