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

Static analysis result for SHA-256 b3cf8cad9d38270e…

MALICIOUS

Office (OLE) / .XLS

525.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2021-05-29
MD5: cf2aecd5c5ebeb080a11def39931dcf5 SHA-1: 12e2ca79200de73ebb3fe2d00cefe96f084781ce SHA-256: b3cf8cad9d38270e3bc9a5d4af2d6cbaea4e766adf17b8cd193cce0feb256a2a
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The presence of an Excel 4.0 macro sheet and a heuristic firing for an enable-lure strongly suggest this file is designed to trick users into enabling macros. The embedded URLs likely serve as destinations for downloading further malicious payloads. No document body text was available for analysis, limiting the ability to determine the specific lure.

Heuristics 5

  • XLM Auto_Open workbook with payload URL or enable-content lure critical OLE_XLM_AUTOOPEN_PAYLOAD_LURE
    Workbook contains an Excel 4.0 macro sheet with Auto_Open / Auto_Close and also exposes a payload URL or enable-content lure in the OLE bytes. This combination is a high-confidence XLM downloader/social-engineering pattern even when formula recovery cannot decode the full macro chain.
  • Excel 4.0 (XLM) macro sheet uses dangerous capability functions high OLE_XLM_DANGEROUS_FN_STATIC
    Workbook contains an Excel 4.0 macro sheet whose formulas reference two or more dangerous capability functions (e.g. CALL into a Win32 API such as URLDownloadToFile, EXEC to launch a process, REGISTER an external DLL procedure, or FWRITE/FOPEN to drop a file) with an Auto_Open / Auto_Close auto-execution name. This is the canonical XLM downloader/dropper shape and is recovered directly from the BIFF records, so it fires even when the full macro chain cannot be deobfuscated.
  • 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 https://rathnakumar.com/BuTxTGO63eD/solo.html In document text (OLE body)
    • https://maidzonemobile.com/Voy4zCN8y1/solo.htmlIn document text (OLE body)