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

Static analysis result for SHA-256 7659bf28cf79da5a…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: b0da2d8b9952f31d6066484a7ff360a9 SHA-1: 84a24170febe51467f435e34d92b3eda001adeca SHA-256: 7659bf28cf79da5abad47d421f1ef9ddd2e0ff6ce236ab3fdb092d50177dbe14
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro uses the RUN function to execute code and a CALL function to invoke 'kernel32.dll' functions, indicating an attempt to execute arbitrary code. The macro also contains a URL, 'https://fisicamp.com/ds/231120.gif', which is likely used to download a second-stage payload. The presence of the Auto_Open macro and the ShellExecute API reference strongly suggest a downloader or dropper functionality.

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.
  • ClamAV: Doc.Downloader.Docusign0521-9864805-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign0521-9864805-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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://fisicamp.com/ds/231120.gif
    • https://fisicamp.com/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
3ee92379b19800bb1e16b96d76e4f31800c6dabf549bf8665d8d4ceab7eae6c0
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6060 bytes