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

Static analysis result for SHA-256 66cb8655a7532909…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 36d2d9154e22d7dc1be8250cb04b28e4 SHA-1: 00cc05f88a61083b01e58ac3d556832d928bc721 SHA-256: 66cb8655a75329094c59b99003cc48092ec72f96687a3efefc1b38a573ba980e
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter

The file contains Excel 4.0 macros that are configured to automatically execute upon opening. These macros utilize the RUN function and CALL to execute a constructed string, which appears to be a call to a Windows API function. The macro also contains a URL, http://me48.ru/ds/231120.gif, which is likely used to download a second-stage payload. The presence of ShellExecute API references and the Auto_Open macro further indicate malicious intent.

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 http://me48.ru/ds/231120.gif
    • http://me48.ru/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
b1a92fcba2ebe2fa90d2bd7eccdde9a9cc031a83a8bf04784dc2cdcfbba2a01a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6292 bytes

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