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

Static analysis result for SHA-256 959172099b2c8d13…

MALICIOUS

Office (OOXML) / .XLSM

110.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: cdaaec40f8db8c05750db11175ca1e80 SHA-1: 14df36d44dd8b8899e24faf8ef5d430c2baef00c SHA-256: 959172099b2c8d135e708d3abcf69a6316fd53916a30b8821bd1445251b21035
188 Risk Score

Malware Insights

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

This XLSM file contains Excel 4.0 macros that utilize dangerous functions like CALL and EXEC. These functions are capable of downloading and executing arbitrary code from external URLs. The presence of hidden sheets and the use of these functions strongly suggest a downloader or droppper functionality. The embedded URLs point to potential payload hosting locations.

Heuristics 6

  • 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: HALT, GOTO, 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 vbaProject.bin — VBA macros present
  • 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://185.45.193.74/44313,6048108796.dat
    • http://195.123.220.175/44313,6048108796.dat
    • http://45.144.29.253/44313,6048108796.dat
    • http://185.45.193.74/
    • http://195.123.220.175/
    • http://45.144.29.253/
    • 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
75218b3f0bb17eeec5572784caf45beb820d0c1786c79b4827590e90358f3168		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 796 bytes
vbaProject_00.bin
f94c515c15a2369b46850e056a403c6ee0151dcf0eaaee0fd438d3a90bd5464f		 vba-project OOXML VBA project: xl/vbaProject.bin 13824 bytes
xlm_sheet_00.xml
3b11ac276e03e0a75147eb42f7fa8acafe7bfdb28b0154bb5f4e04a17633ef7a		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4291 bytes
xlm_sheet_01.xml
a5fc80b1569128bd0323daacf4b0484b147d9d37755aacc26435ea011bd9f0cd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2111 bytes
xlm_sheet_02.xml
a6c079d2a564b952bdc7f60d49402489a374e91f07f8b51ef328523d2a650900		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1944 bytes

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