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

Static analysis result for SHA-256 09ddd01a2e74cba8…

MALICIOUS

Office (OLE) / .XLS

426.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: a314a173f3f4824b715872ba8c9f6795 SHA-1: 2a1f8788f9ac3d71d36094950fe8418d026fe271 SHA-256: 09ddd01a2e74cba8a5ed907a1b64ad9cb6d0e8c638eb7080c6cdc07cd3226896
382 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The sample is an Excel file containing both VBA and Excel 4.0 (XLM) macros. The XLM macros contain references to dangerous functions like RUN and URLDownloadToFile, and reconstruct a URL from cell data. The VBA macro contains a Workbook_Open event that calls Application.Quit, which is likely a decoy or part of a larger obfuscation scheme. The presence of the 'enable macros' lure and the URLDownloadToFile API call strongly suggest the document's purpose is to download and execute a second-stage payload from the URL http://enginotelfinike.com/19.gif.

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://enginotelfinike.com/19.gif
    • http://enginotelfinike.com/19.gif�
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e26e570691e37538cb153a294d4bd7899ebc79f39ec63fd34cf1eae37efa26f6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9455 bytes
macros.bas
8c21c322bb8b23e7dbfa4da0de1c41676162b0810e96582d1365413c12adc768		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 977 bytes

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