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

Static analysis result for SHA-256 0c6197dafbfa860e…

MALICIOUS

Office (OOXML) / .XLSM

217.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 998a57ac2c7a6f7cbc428e372f3f5105 SHA-1: 693a14e136591dd065b1ccba7d4dde5916c93017 SHA-256: 0c6197dafbfa860ec73ce5016223fb6203ec744cf59ed2a820336447fe05d3a3
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an XLSM file containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous XLM functions like FORMULA and CALL to download and execute a second-stage payload from the provided URLs. The Auto_Open macro is present, indicating immediate execution upon opening the document.

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.
  • Dangerous XLM formula APIs: FORMULA, GOTO, HALT, REGISTER, EXEC 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.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 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://91.211.91.71/
    • http://190.14.37.252/44313,6048108796.dat
    • http://91.211.91.71/44313,6048108796.dat
    • http://185.82.218.30/44313,6048108796.dat
    • http://190.14.37.252/
    • http://185.82.218.30/
    • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
125e232ed61153a54047fc42bf831a7a5df16598df76aff16860bf28521d2ade
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2760 bytes
vbaProject_00.bin
590b0126ca8d1e7bd88af1d58b85b0c62ce22d8c6fa543f2326f7f6b9b0e0d64
vba-project OOXML VBA project: xl/vbaProject.bin 13312 bytes
xlm_sheet_00.xml
6d2c54826d9f8cfbc27ceceafde259a335d4f7ce95274c4c00b5379894a0c3cc
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4413 bytes
xlm_sheet_01.xml
9ca9d23ba3a5b04b35f5c4332df1ce68c0463c9fa42327aa2f7cde6c21f3e64c
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2121 bytes
xlm_sheet_02.xml
5e80fd069ac35c5e39918d8dfaaf0ba77875f57b487bcfcc5d8bc7d346806551
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1832 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).