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

Static analysis result for SHA-256 973e51a1f7437e25…

MALICIOUS

Office (OOXML) / .XLSM

84.8 KB Created: 2021-02-17 21:46:36 UTC Authoring application: Microsoft Excel 16.0300
MD5: 418efb6790fc20e7e961d6585a6baec5 SHA-1: 839913b96999373058a3dd868712bd65fda860e5 SHA-256: 973e51a1f7437e25537b2b355779653cbc82866df0185e3549eb3fc0b7accd39
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.003 Windows Command Shell

This XLSM file contains a Workbook_Open macro that utilizes VBA character-shift decoding to execute a command via the Shell() function. This indicates the macro is designed to download and execute a second-stage payload. No specific family could be identified, but the technique is common for initial access.

Heuristics 6

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Suspicious extracted artifact high 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present
  • 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.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
418ecb668d5e9e860d0ea5b66f3ab7ed0faa0abc3491effc2fad1716f155c7b4		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 19690 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.
vbaProject_00.bin
29dde0e03b8e4c7b8e1889739cd97807147bc25183397565e9d25f448df2b72c		 vba-project OOXML VBA project: xl/vbaProject.bin 29184 bytes

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