Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 7df32ebcbcf64f1e…

MALICIOUS

Office (OOXML) / .XLSM

258.1 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: 533b4630cf5f95be1aae17d23f93eecc SHA-1: 4ffe04df25200f95c6a26c0435c236d201c90a51 SHA-256: 7df32ebcbcf64f1ec3854cea7cd33af47aa721d7a1e099ddacd09d5f169a6b22
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic, VBScript, and JScript T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

This XLSM file contains Excel 4.0 macros, indicated by the OOXML_XLM_MACROSHEET heuristic. The macros utilize dangerous functions like FOPEN, FWRITE, and EXEC, as identified by the OOXML_XLM_DANGEROUS_FN heuristic. Specifically, the macro reconstructs the path 'C:\ProgramData\kKWPOkjwfqV.sct' and uses FOPEN to open it, suggesting it will write malicious content to this file. The presence of an Auto_Open defined name (OOXML_XLM_AUTOOPEN_DEFINEDNAME) indicates that these macros will execute automatically upon opening the document. The script's intent is to download and execute a second-stage payload.

Heuristics 5

  • 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: FOPEN, FWRITE, FCLOSE, EXEC, HALT 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.

FilenameKindSourceSize
xlm_sheet_00.xml
bdce1f2a5d7f1a704f51039d8b4cca1cfc672b9244740eeaaf0050a2c0eda04f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 755849 bytes

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