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

Static analysis result for SHA-256 7f262bf662154e10…

MALICIOUS

Office (OLE) / .XLS

88.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 9122c9b7eb8f8e6ec8b683fff4909415 SHA-1: 8de0424562c3804612709cf7764a8b051191a65b SHA-256: 7f262bf662154e10f075e15218d12b9c9d34f05082db958f4f91f08d6d5068a7
222 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, including an Auto_Open entry, which is a strong indicator of malicious intent. The macros are designed to execute dangerous functions and reconstruct a URL, likely for downloading a second-stage payload. The presence of a macro-enable lure further supports the malicious nature of the document.

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), across individual numeric cells (one ASCII charcode per cell), or split across multi-char fragment cells a download formula concatenates by reference (=A1&A2&… / CONCATENATE(...)). 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, LABELSST/RK/NUMBER cells, and FORMULA cell-reference concatenation in token order.
  • 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://fb25d3eda23hfy.com/fb26.gif�
    • http://fb25d3eda23hfy.com/fb26.gif

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f0b0979912ef00eef93b7df46bfb904d31b72a8b992d8cde7cb6b6f68d020300		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2353 bytes

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