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

Static analysis result for SHA-256 0a2a59ec619fe14e…

MALICIOUS

Office (OLE) / .XLSX

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-27
MD5: 76b564c44ae8310f2c6353f2e209f663 SHA-1: 53601695d5943036a3e8f4b93f1fc7dfe2a10754 SHA-256: 0a2a59ec619fe14ee8f2bd86590fb4ce2ce1f59c93f098a946c0e81a01a0e1e9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a known technique for executing malicious code. The macros likely leverage dangerous formula APIs, such as RUN, to download and execute a second-stage payload from one of the embedded URLs. The presence of multiple URLs suggests a fallback mechanism or a distribution strategy.

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
699e21f010c7c5f5713063f52e691ec519f766e81393f8793f7a585cd43d5349
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7635 bytes