Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 8a2b0fe07c437a22…

MALICIOUS

Office (OLE) / .XLSX

125.0 KB Created: 2021-10-27 10:31:49 Authoring application: Microsoft Excel
MD5: 1909b272d9181868d904bd61217e70d6 SHA-1: befff61f7812a7e6cbdf4c72fcf3703c62f49992 SHA-256: 8a2b0fe07c437a225d7457891b09f617cccb9dc84c237d7c1ff34a913eeda804
82 Risk Score

Malware Insights

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

The presence of an Excel 4.0 macro sheet (OLE_XLM_AUTOOPEN) indicates malicious intent. The macro reconstructs the path 'C:\ProgramData\rdBaMtWgp e.vbs' and attempts to open it using FOPEN. It also references three URLs, likely for downloading the payload. The macro's primary function appears to be downloading and executing a secondary payload from the embedded URLs.

Heuristics 3

  • URL reconstructed from XLM cell array (3 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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 https://cdn.discordapp.com/attachments/911255825308348439/917344562354221086/bfugrKhVwhatsupmotherfuckers.bin
    • https://cdn.discordapp.com/attachments/911255825308348439/917344555379085402/efrXXwhatsupmotherfuckers.bin
    • https://cdn.discordapp.com/attachments/911255825308348439/917344568125562890/GuJPZwmNijUwhatsupmotherfuckers.bin

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
36829b97dcc8f011d7223dd5d456d42e4cd07f59c645bd5455bc18b510406002		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2308 bytes

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