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

Static analysis result for SHA-256 37ebb08940661dbf…

MALICIOUS

Office (OLE) / .XLS

59.5 KB Created: 2020-05-25 07:38:15 Authoring application: Microsoft Excel
MD5: a2e0b1372f89d8e84cd15b35956b9499 SHA-1: 3005e607c16d5fd884d07663c75e27cc2adc645c SHA-256: 37ebb08940661dbfa35a8cca0a0cec36e3baab6648c4acddfdc25d8093cfb4a1
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known technique for executing malicious code. The macro sheet contains a formula that reconstructs a URL, likely for downloading and executing a second-stage payload. The reconstructed URL is http://gsax.ecowinmurzxCQKMVLfETjcvPURONDFAJSy.

Heuristics 3

  • 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.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
75a24257354b59a6c21f1b70429b6ee1c7afcb679ece9a1912080145bee7ae37		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 34477 bytes

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