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

Static analysis result for SHA-256 5bb170f9832bb8f9…

MALICIOUS

Office (OLE) / .XLSX

329.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: cd3fcfebeb534de854e89f2c40b5751a SHA-1: 8b313849c58d183b11fc3ff0ef2362b0fbf86e3b SHA-256: 5bb170f9832bb8f9cf5eca509bca9f558be2499375200516303cc21000ebc2b4
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File: User Execution T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros with an Auto_Open entry, which is a critical finding indicating automatic execution upon opening. The macros utilize the RUN function to execute commands and construct a URL from concatenated strings, pointing to 'http://i.sfu.edu.ph/ds/161120.gif'. This strongly suggests the file acts as a downloader for a second-stage payload.

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://i.sfu.edu.ph/ds/161120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e17e7cc4a238aa7ef2e84a739a77bbc946bb2881b6aa82203097e9ab8210d20f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6273 bytes

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