Office (OOXML) / .XLSX malware analysis — malicious · 2d8ff1018eab9fd4

MALICIOUS

Office (OOXML) / .XLSX

233.7 KB Created: 2021-03-05 04:08:28 UTC Authoring application: Microsoft Excel 16.0300

MD5: 8cedff60a76df7b862602542787f9d42 SHA-1: e4e89f465f27e171e48e43d5e9c6005302d06aae SHA-256: 2d8ff1018eab9fd4ed72d8e3083db92eb924965706df0425ccb4470190034510

120 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The sample is an Excel file containing Excel 4.0 macros, as indicated by the OOXML_XLM_MACROSHEET heuristic. The ClamAV detection further confirms its malicious nature as a downloader. While the macro content is truncated, the presence of Excel 4.0 macros strongly suggests an attempt to download and execute a second-stage payload, a common technique for malware delivery.

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.
ClamAV: Doc.Downloader.Trojan-bf70f023603538ee-bf70f023603538ee-9950269-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Downloader.Trojan-bf70f023603538ee-bf70f023603538ee-9950269-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `473b5cada552ae19b3048201865497367dfca7404c7cd2a47bc7bf50493ebd7d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	11364 bytes

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