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

Static analysis result for SHA-256 7ea822ff2f4b6b02…

MALICIOUS

Office (OLE) / .XLS

740.5 KB Created: 2001-12-31 21:23:00 Authoring application: Microsoft Excel
MD5: bd0bf65155335f2984f2a5b98ed61f37 SHA-1: 33b590c7d2cf35940c8f09eabb901aba07a44d26 SHA-256: 7ea822ff2f4b6b024c6881bb8675a6d1d2929b8169a0a7fb72b4b030eb7cbcf0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro, which is a critical indicator of malicious intent. The macro utilizes dangerous functions, including 'RUN', suggesting it is designed to execute arbitrary commands. The document body contains a list of engineering textbooks, which appears to be a lure to disguise the malicious macro functionality.

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
5e5f6fcae6a39b10a949ecef038d4c519a3699306611463a249a4db58dbd3a2c
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 90123 bytes