Office (OOXML) / .XLSX malware analysis — malicious · a49506cf573f268c

MALICIOUS

Office (OOXML) / .XLSX

113.7 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000

MD5: 54fad19ba4e76a7d97f2bb77e35c0a7a SHA-1: 09d5cd9a09ef841a552c49a7dd6028fafbbab0b0 SHA-256: a49506cf573f268cdfe056fe9ba08c1b74bd01dd0bc427a3185be7842e22deb0

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The sample is an Excel file containing a critical heuristic firing for Excel 4.0 macros. The macro sheet contains obfuscated commands that appear to construct a path to execute a file named 'a.exe' from the 'Startup' directory. This indicates a likely intent to establish persistence and execute a malicious payload.

Heuristics 1

Excel 4.0 macro sheet (1 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `69fb09a7f8abb54cf6cbd33842042a2cf39e274ef1aba64162406a86273f3f3a`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	4638 bytes

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