Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fe18033e4231a2d1…

MALICIOUS

Office (OLE)

173.0 KB Created: 2020-05-13 06:54:45 Authoring application: Microsoft Excel
MD5: 4d4fb258047a67d4f83a551a2865cf61 SHA-1: 768b817408271dd553b6e371e7cbe90e0d7a45ce SHA-256: fe18033e4231a2d1364599d1d1bf8ab9735570bb645921015f0b37b1b9a005cb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The macro uses dangerous functions like RUN and SET.VALUE, indicating an intent to execute arbitrary commands. The script also attempts to construct strings using character manipulation, likely to obfuscate the final payload or command. The presence of these elements strongly suggests the file is designed to download and execute a secondary payload.

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
a967adddae58ac937c1f7d5f0a84ce353b69998761328786b743598ef4343144
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 128421 bytes