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

Static analysis result for SHA-256 060cee5357ed6f80…

MALICIOUS

Office (OOXML) / .XLSM

320.0 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: b7822ebc4c140c0b96663b63680945a4 SHA-1: 8299e072939cdc3acf831473bc45e67f17d252a7 SHA-256: 060cee5357ed6f807e908dffd3ede82d8f1403571e92b6d7db468f2803a3ba10
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros. These macros are configured to execute a script file named 'aeXNsDFSgcg.sct' located in the 'C:\ProgramData\' directory. The use of dangerous XLM functions like FOPEN, FWRITE, FCLOSE, EXEC, and HALT indicates the intent to download and execute a second-stage payload. The Auto_Open defined name further suggests automatic execution upon opening the workbook.

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
8b579335242c2b07e60a8aac1e3a69de0c2fb2f5b1be0222fc62456d3c25959c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1629350 bytes

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