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

Static analysis result for SHA-256 005bb8f3c10c455a…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: e1d4b6360fb3d156f37dc7f8b57aa9ea SHA-1: 66820ebd1f2937f726643f7e243e04336e5824d4 SHA-256: 005bb8f3c10c455a258e524172841b269ae977042135ab708ad252641b2edd9b
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

The sample contains Excel 4.0 macros with an Auto_Open defined name, indicating an attempt to automatically execute code upon opening. The macros utilize dangerous functions like RUN and CALL, and construct strings such as 'Key32' and 'Crea' which are likely part of a payload download or execution chain. The embedded URL 'https://ctxpress.com/ds/261120.gif' is highly suspicious and likely serves as a download source for a secondary stage. The ClamAV detection further supports its malicious nature.

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://ctxpress.com/ds/261120.gif
    • https://ctxpress.com/ds/261120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
aa837a287543a9593dc9ad53c5a1043539349d9d7158b9d02f92e2bb7330dc0f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6677 bytes

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