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

Static analysis result for SHA-256 22125fcc284dbb80…

MALICIOUS

Office (OOXML) / .XLSM

200.4 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: 686934b578a0670a3cfe05a66db3dd69 SHA-1: d60ff89656f0ad1b554e3216cde5b4242d172f23 SHA-256: 22125fcc284dbb800f213dd0d59443a61a3eebc16b97557c5ec092326d78df12
218 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious Macro T1059.005 Command and Scripting Interpreter: Visual Basic T1218.011 System Binary Proxy Execution: Rundll32 T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like FOPEN, FWRITE, FCLOSE, and EXEC to download and execute a second-stage payload. Specifically, the macro constructs the path 'C:\ProgramData\xhosVulBTp.sct' and likely uses it to save a downloaded script. The presence of an external hyperlink to 'www.shipco.com' suggests a potential lure or command and control channel.

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
5cf807b495b2fb960fd10be3e12dcc73af4a4c8b64f012d192f2893eadce3bcb		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 707421 bytes

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