Office (OOXML) / .XLSM malware analysis — malicious · 54b3dbb42c61fab8

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 612f49670fd065b0d6b75400d9644827 SHA-1: 04998046e8681c55506e534aa283e5e5cb87643b SHA-256: 54b3dbb42c61fab8d31be2edeb0668a0f2e50ee275fae3d5df6b27f26001b5ca

250 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter T1071.001 Application Layer Command and Scripting T1566.001 Phishing T1071.002 Automated Open of Existing Files

The file utilizes Excel 4.0 macros, specifically leveraging the dangerous formula APIs (=CALL, =EXEC, =REGISTER, =FORMULA) which are commonly used in XLM-based droppers to bypass VBA security controls and execute arbitrary code. The presence of hidden sheets further supports the concealment of malicious code. The detected ClamAV signature confirms the malicious nature of the file. The URLs are standard OpenXML formats, likely used to deliver the malicious macro content. The file's structure and the use of XLM macros strongly indicate a downloader attempting to establish a foothold on the system.

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, GOTO, REGISTER, 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.
ClamAV: Xls.Downloader.GreenEnable06210-9869360-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.GreenEnable06210-9869360-0
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 10 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` `a59fc544cb8b2d600fcfc478b6d758f14bb5a970dcbd7bed9b6381d0fa65ddcb`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml	3233 bytes
`xlm_sheet_01.xml` `716d1708b78778701c84eaf2d848c4aa6dbc859a82080c58f06a0fbf48f39542`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml	1785 bytes
`xlm_sheet_02.xml` `ee53724c013f6d80cfb10a8b258801e38cf83ba9a7366385139d3838a400abd3`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml	2308 bytes
`xlm_sheet_03.xml` `cd3ab4b8e7330421af8fef3b07d1c240d54bea1ef413297f8b55501b9a0e2772`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml	1587 bytes
`xlm_sheet_04.xml` `6b118fd093ce5f52799b56aa29ca562e201fc37655267d384c84fbe05ec198aa`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml	1587 bytes
`xlm_sheet_05.xml` `d86382cd48cf5b090eb645f7251494f82b2e8c61e4e94a94ba295a5a9a8c628b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.xml	1580 bytes
`xlm_sheet_06.xml` `564a12d089bea2438d54307bbe41077c7c199180e2f4d57332081b6e2b2c2cb6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.xml	1586 bytes
`xlm_sheet_07.xml` `66150b001e8a7524a17d0bdcfa2d5a5d387a75b9c9ca16a1d1bba19ccb52a96e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.xml	1583 bytes
`xlm_sheet_08.xml` `32deba180b1d50bf8dc140f42042696af27da0b8d8f58ce045bea4a1bef5015c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.xml	1561 bytes
`xlm_sheet_09.xml` `867a6ad5ec743bf32bd430da32ba770bbe97c8032cc70b36d5f7b25b690caefe`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1498 bytes

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