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

Static analysis result for SHA-256 87a3493c25c57905…

MALICIOUS

Office (OLE) / .XLSX

329.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 7cb43c3bf4ab2ec81d58696b0ac69816 SHA-1: a5d35f33a6630b753774f81d10491549b2ebd8a7 SHA-256: 87a3493c25c579051e5d17e5c6f1dea4d2c802441f39b2f103716b833fd01761
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The SC_STR_SHELLEXEC heuristic confirms the use of the ShellExecute API, which is often used to download and execute secondary payloads. The embedded URL `https://nomzoo.ml/ds/161120.gif` is highly suspicious and likely serves as the distribution point for the payload. The ClamAV detection further supports the malicious nature of the file.

Heuristics 5

  • 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
  • XLM Auto_Open with dangerous formula APIs high 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.
  • 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://nomzoo.ml/ds/161120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
b74fbb14c9dd0283fe5b35630158622cf58bbddcd03d161d30bf64d1f40271a4
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7889 bytes