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

Static analysis result for SHA-256 af396d76ccc14aa0…

MALICIOUS

Office (OOXML) / .XLSM

49.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-09
MD5: 141e13e5294a4d240b711e0cfc02d561 SHA-1: a5f5bab62b933549451b157cc8bba7c77f1f90ab SHA-256: af396d76ccc14aa0d54d2e1a8ae90fd0f48498a29fe2779b2fbc957cb8662cf7
290 Risk Score

Malware Insights

MITRE ATT&CK
T1218.010 System Binary Proxy Execution: Regsvr32 T1059.005 Command and Scripting Interpreter: Visual Basic T1105 Ingress Tool Transfer

This Excel 4.0 macro-enabled document (XLSM) utilizes dangerous XLM formula APIs to download and execute a payload. The heuristic 'SE_LOLBIN_RUN_COMMAND' specifically indicates the use of 'regsvr32.exe' with URLs pointing to potential payloads. The reconstructed command line suggests an attempt to download and execute a file from 'http://retailhpsinterview.com/search/yNbsL/'. The presence of multiple suspicious URLs and the critical XLM macro sheet firings strongly indicate a malicious downloader.

Heuristics 7

  • Excel 4.0 macro sheet (3 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: FORMULA 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.
  • ClamAV: Win.Malware.Agent-9982905-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Agent-9982905-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 5 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://retailhpsinterview.com/search/yNbsL/
    • http://www.agnesleung.com/raw.backup/p8D6ttXDaNwd/
    • https://pakistannakliye.com/Dodonian/tSasxFCiQXxh5Qvin/
    • http://www.agretto.com/Template/pnM0iPs4b2IfR7XY7v/
    • https://gsmjordan.com/SupplierPanel/XII/
    • http://retailhpsintervie
    • http://xnxx.c1.biz/images/iJNVpahOW4CBuidDD66/
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
f04a70b64ec63683784ca39bae294e6b2c7841eff011398f4b35767fb86e93c1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3899 bytes
xlm_sheet_01.xml
ca7fa26ed4d58d3fd46ef9dc8387e336f3ef9d70dc5dd78639bf3c2c5e458528		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1277 bytes
xlm_sheet_02.xml
0b61b2dde0ca331ea31d988c051388a2c4d7c70e05fe1946e85ab2c205e9d956		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1221 bytes

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