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

Static analysis result for SHA-256 664f4ab87eca073f…

MALICIOUS

Office (OLE) / .XLS

50.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 7766f6b4350d804402382756f4aaf0cd SHA-1: a052b5f2981c77072a88ed352b1704ebbbf06a75 SHA-256: 664f4ab87eca073fe888f387f5a52f4f16c4283bd11505141dcd4a2b3f64c535
222 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros with an Auto_Open entry, indicating automatic execution upon opening. These macros are designed to download a file from the provided URL, likely an executable, and the document body contains text that attempts to lure the user into enabling macros. The presence of dangerous formula APIs and the reconstruction of URLs from cell arrays strongly suggest a malicious downloader.

Heuristics 6

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • URL reconstructed from XLM cell array (1 URL) 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://foundation.shanto-mariamfoundation.org/24.gifDa
    • http://foundation.shanto-mariamfoundation.org/24.gif�
    • http://foundation.shanto-mariamfoundation.org/24.gif

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
b85a04030ee15a5823afbe8a5c58782f7c760714b2f75fcf902d376138ea1320		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2772 bytes

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