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

Static analysis result for SHA-256 0dcc1b5b598feebe…

MALICIOUS

Office (OLE) / .XLS

62.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: c868a58c4f123356bbca31beaa14c0cc SHA-1: 1782c760050d9230c07c07de71d3402c8e209ee4 SHA-256: 0dcc1b5b598feebe2741b55c6cb38aef9da482f95d4b42d81b7f1c0092e9330b
382 Risk Score

Malware Insights

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

The sample contains both VBA and Excel 4.0 (XLM) macros. The XLM macros are configured to auto-execute and utilize the RUN function, indicating an attempt to download and execute a payload. The Workbook_Open VBA macro explicitly calls Application.Quit, which is unusual and may be an attempt to hide execution or prevent further interaction. The presence of URLDownloadToFile API calls and an embedded URL strongly suggests the macro is intended to download and execute a second-stage payload.

Heuristics 10

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • 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.
  • URL reconstructed from XLM cell array (1 URL) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://blog.vokasidev.com/crun20.gif
    • http://blog.vokasidev.com/crun20.gif�

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
d4222e1ad83b892546402a65bce1342319760d5f0e17d0c73ae5f07e792beb86		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9447 bytes
macros.bas
c29faf2da8b6b84c63880f8f3ff09f138acdaa94ad9406cab75b546ae0e54428		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 979 bytes

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