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

Static analysis result for SHA-256 86ad09a41082bceb…

MALICIOUS

Office (OLE) / .XLSX

139.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: dde6d194988f495feaee55bc395bc725 SHA-1: e2aaeac1d44cf10d89d3dbe28c6e60672c0f8e0f SHA-256: 86ad09a41082bcebe51d62689885197969fa23b7f2a860c41bd002ae623a55e9
262 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a strong indicator of malicious intent. These macros are designed to execute and download a payload from one of the five embedded URLs. The presence of 'DllRegisterServer' and 'SysWow64\Windows\' suggests an attempt to register a component or execute code within the system's directories.

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.
  • URL reconstructed from XLM cell array (5 URLs) 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), across individual numeric cells (one ASCII charcode per cell), or split across multi-char fragment cells a download formula concatenates by reference (=A1&A2&… / CONCATENATE(...)). 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, LABELSST/RK/NUMBER cells, and FORMULA cell-reference concatenation in token order.
  • ClamAV: Doc.Downloader.EmotetRed02222-9938635-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02222-9938635-0
  • 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://canopuseng.in/b/5G1sl6x/
    • http://sesco-ks.com/wp-content/rDARACyF1lDOz9GP1r/
    • http://dev.learncaraudio.com/wp-admin/v6IKIDu90k8C6Y8/
    • http://fastxmfg.com/voluptatum-voluptatum/rh2CNMHNjdgb6/
    • http://sep.dfwsolar.club/hzh3v/c083ujO5b11tuo92/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f459bbc7010b3c85969ff63ef843cbb5e7e74898bddba8eda2f959641ace8b9e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6401 bytes

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