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

Static analysis result for SHA-256 3142bc951ea27400…

MALICIOUS

Office (OLE) / .XLS

336.5 KB Created: 2021-08-16 09:36:27 Authoring application: Microsoft Excel
MD5: 18f045d859a6060472377efa72348d6d SHA-1: 48e97ba04db073e8de2bdb13ef504677fd83d665 SHA-256: 3142bc951ea2740040575674e526eca2eb0dd2025f091c11c9e0e0ce8a551f8b
242 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 macro, which is a critical indicator of malicious intent. The macro is designed to execute dangerous functions, including opening files and running external commands. It reconstructs and uses URLs to download and execute a second-stage payload, likely involving mshta.exe, as indicated by the SC_STR_MSHTA heuristic.

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) 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 mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • 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://alliancefinancebank.com/images2/2uyv6x53xzch74.php
    • https://jalmalapillingworks.com/data1/images/wyO1CgtcN.php
    • https://space.egematey.com/wp-content/cache/wpfc-mobile-cache/proclus-the-quaestor/amp/9wRRDuE5lTS6tNl.php
    • https://nileshengineering.co.in/img/autoparts/iyiY4t35k.php
    • https://bitcoinventures-investment.com/use.fontawesome.com/releases/v5.8.1/ijescZBVjWuE067.php

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
81cdae635aad8696fa23cde9d7313804c202cba7176d2c22afbd2627e46150d4		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 820 bytes

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