Office (OOXML) / .XLSX malware analysis — malicious · c1b70fb4d8100bee

MALICIOUS

Office (OOXML) / .XLSX

83.6 KB Created: 2021-02-03 15:28:44 UTC Authoring application: Microsoft Excel 16.0300

MD5: 627887f5f6c27aac6f930e93f5c20da6 SHA-1: 7688ec0e7a05f582b1b84883f44c88b8739a2b3c SHA-256: c1b70fb4d8100bee0ed1775e84b22375424a5654de1d2d6eee6364b2a9ad8952

120 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1059.005 Visual Basic

The sample is an OOXML file containing a disguised Excel 4.0 macro sheet, indicated by the 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_DISGUISED_RELATIONSHIP' heuristics. The presence of Excel 4.0 macros suggests an attempt to execute arbitrary code upon opening. No specific IOCs like URLs or hashes were extracted from the truncated script content.

Heuristics 2

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.
Excel 4.0 macro sheet stored under disguised package path critical OOXML_XLM_DISGUISED_RELATIONSHIP

OOXML package declares an xlMacrosheet relationship whose target is outside the canonical xl/macrosheets/ path. Excel follows the relationship type, while path-only scanners can miss the macro execution surface.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `b54f30fe6f8885dd51f662a38241a5f0bc1ed77a7e1990fcc2e8efb2cb29825b`	xlm-macrosheet	OOXML XLM macro sheet: xl/dd/sheet1.bin	1031511 bytes

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