Office (OOXML) / .XLSM malware analysis — malicious · e35f91df736a6afe

MALICIOUS

Office (OOXML) / .XLSM

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

MD5: 784e64bbacb6237e11d886574d0ecfad SHA-1: 93628ffbac62a3b7a5e9004cbc860768d22038ed SHA-256: e35f91df736a6afea02f76506d20d18e5b175c1d625c4bfd2c3304d446f88bf5

130 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an XLSM document containing Excel 4.0 macros. These macros are used to construct a VBScript payload by concatenating strings and character codes. The script appears to be designed to write a file to 'C:\ProgramData\TjLhZMnMufAQm.vbs' and then execute it. The use of dangerous XLM functions like FOPEN, FWRITE, and EXEC, along with the construction of a VBScript, strongly suggests a downloader or initial execution stage for further malicious activity.

Heuristics 4

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.
Dangerous XLM formula APIs: FOPEN, FWRITE, FCLOSE, EXEC, RETURN critical OOXML_XLM_DANGEROUS_FN

Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
- http://schemas.microsoft.com/office/excel/2006/main
- http://schemas.openxmlformats.org/officeDocument/2006/relationships

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `ed9b2a2575d1e63c556feeac6398bada82e2716bc8235645384e7f6be9702f8f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	5289 bytes

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