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

Static analysis result for SHA-256 62971be564f3e13c…

MALICIOUS

Office (OOXML) / .XLSM

193.5 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: bf42bf320260f0904ab128a2458bf063 SHA-1: 0309867e0a70dda24cd912be7bdb369938fcce04 SHA-256: 62971be564f3e13cbdbb1215e1baa930d812233cf32f8db12aa2ceb1f211418d
218 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an XLSM file that uses a lure to prompt the user to enable macros. Critical heuristics indicate the presence of Excel 4.0 macros, including dangerous functions like EXEC and CALL, which are used to download and execute payloads. The macro code constructs a path to a SCT file in ProgramData, suggesting it's designed to download and run a second-stage payload.

Heuristics 7

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • External hyperlinks (1) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 1 external hyperlink — clickable URLs are stored as external relationships. First target: http://www.shipco.com/ecommerce/sch/scheduleindex.php
  • 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://www.shipco.com/ecommerce/sch/scheduleindex.php
    • 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
db7118c5e7d18eead5ccce9e44bd34f3e30ba3b5c9a9121510f5d18be17f4daf		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 681934 bytes

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