Office (OOXML) / .XLSX malware analysis — malicious · 7ae09fa7d547fafb

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 2f3a0e8809690139a12f6c9555260b8f SHA-1: 45430104adf420ad265a657a8e04f03139107674 SHA-256: 7ae09fa7d547fafb1cd1b8c7127f8667e88b915d89c6bdf52e178a78ff279955

180 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File

The sample is an XLSX file containing multiple Excel 4.0 macro sheets, as indicated by the OOXML_XLM_MACROSHEET and OOXML_XLSB_INTL_MACROSHEET_IN_XLSX heuristics. One of the macro sheets contains the string "URLDownloadToFile", which is a strong indicator of a downloader functionality. This suggests the macro is intended to download and execute a second-stage payload from a remote URL. The ClamAV detection further confirms its malicious nature.

Heuristics 3

Excel 4.0 macro sheet (13 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
XLSB international XLM macro sheet hidden in .xlsx critical OOXML_XLSB_INTL_MACROSHEET_IN_XLSX

OOXML package is named .xlsx but contains XLSB workbook parts and an international Excel 4.0 macro sheet. This hides XLM macro execution from scanners that trust the extension or only inspect XML worksheet parts. The technique is macro execution, not a document-parser CVE.
ClamAV: Xls.Downloader.GreenOffice01220-9937699-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.GreenOffice01220-9937699-0

Extracted artifacts 13

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `08b2a21dfd49ba82acc3e98fa2548503ea70375384baae9690f9b9f92ee72a12`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin	363 bytes
`xlm_sheet_01.bin` `75486df1e8fdc8dfcfa9347e2efdacc8c653c3f2057c715406ef8db6742ee804`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet2.bin	632 bytes
`xlm_sheet_02.bin` `62069c771b71f4e449852a9717d0e3ee529ecca6497ff21cb92f7f53c4d1b43c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	2766 bytes
`xlm_sheet_03.bin` `ae5e83e6d426668a5db416906d420732f1fdd9591d423b86f2b9f1dcd9fa44ac`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet3.bin	1619 bytes
`xlm_sheet_04.bin` `2cd9dbeea24ca020fd0a4017b931dd97c95e7c0ab519355790f0ba447b4a3039`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet4.bin	573 bytes
`xlm_sheet_05.bin` `5009dc8e79faedbbf6d81cc8ab84c37fddbbf642b83acb0a4f501b89844ac3ca`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet5.bin	618 bytes
`xlm_sheet_06.bin` `cd13478f2e3c7cf4b2507e646c0ceb5fea3e2f93cca4db2727dc940a10700abb`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet6.bin	766 bytes
`xlm_sheet_07.bin` `d6cbc03e36305aa993ba351dfcc3c9f2613ba6f5108c24fb559e4b12cff76c9e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet7.bin	472 bytes
`xlm_sheet_08.bin` `fe33ad0661ee70bb32c1080c3584fa621afd5781d67903179cd30bf602806937`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet8.bin	423 bytes
`xlm_sheet_09.bin` `ff4e973b54b80c00d226e9c4a283940eb8435e9810d5d202ee1f5db363852b06`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.bin	754 bytes
`xlm_sheet_10.bin` `6136e300f8261bd0e71a47aed8dd19bafdab22d27cb4eaa966ba836779f08b49`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet3.bin	679 bytes
`xlm_sheet_11.bin` `46a26398a13684a16d8ede38746c526be4025503508fe8a89a3748973af9a2d3`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet4.bin	799 bytes
`xlm_sheet_12.bin` `52cbcb9c330923e6a38883615db2b9d510da997b15c7142598ab08d9f0a99559`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/intlsheet9.bin	619 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.