Office (OOXML) / .XLSX malware analysis — malicious · efcaf7364573f206

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 4b4e0da78d069ad63be8a2bd0756b7ac SHA-1: 10c7015406e5f80fc489ae1efdef99404aa5aacc SHA-256: efcaf7364573f2064721587d5ccfa6ceea6f89b1963c7f2e09ba20514431dcb7

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. The extracted macro content, though truncated and partially obfuscated, shows commands that appear to be constructing file paths, suggesting an attempt to execute arbitrary code or download a secondary payload. The repeated construction of 'C:\Program Files\Common Files\System\Acrobat\AdobeGCClient.exe' points to a potential attempt to masquerade as a legitimate Adobe process or to place a malicious executable in a common program directory.

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` `4b8369e3e4828c0b3b0b3c4079a00e6c1e17bae3741745e88391febff04e2823`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	7493 bytes

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