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

Static analysis result for SHA-256 aaefbdd6973024a7…

MALICIOUS

Office (OOXML) / .XLSM

81.2 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 8e8d541cfef1333f13488664cc663aba SHA-1: 7f9038834647a726146dc2ef5d40ea19d16ac3d9 SHA-256: aaefbdd6973024a71ebc3e0b31c247c703b2d2e641a9c63608e83f79a9e621ca
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File T1059.001 PowerShell

The file contains Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' heuristic. The 'OOXML_XLM_DANGEROUS_FN' heuristic specifically flags the use of dangerous functions like 'CALL' and 'EXEC', which are commonly used to download and execute arbitrary code. The embedded URL 'http://drt22uhfjmz03ltxc.xyz/grays.gif' is likely the source of the payload. The presence of an 'Auto_Open' macro suggests automatic execution upon opening the document.

Heuristics 4

  • 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, CALL, HALT, 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.
  • 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://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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
7cc29e0426c044da329e809d130552193749e3486fd84097688f127f76120087
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5778 bytes
xlm_sheet_01.xml
5e0b317bc9eef478a9b391aa848d4ca25c6a2921bbc6af4ad6fc140f76188572
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 963 bytes
xlm_sheet_02.xml
98345195494abbd762f0f368955be9eed2dfec729c77fce42164df297eed179f
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3090 bytes