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

Static analysis result for SHA-256 564c4a4fdfae5ffc…

MALICIOUS

Office (OLE) / .XLS

41.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: bc2b1a53d3af3b7ec9b9154208233548 SHA-1: 36f06ef393881d1c7b398707835a559d7b741d1f SHA-256: 564c4a4fdfae5ffc4daae1e83119c7f859209b82b60416b90c42c392dc93f062
140 Risk Score

Malware Insights

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

The sample contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding. The heuristics indicate that this Auto_Open macro uses dangerous formula APIs, including the 'RUN' function, suggesting it is designed to execute arbitrary commands. This is a common technique for downloading and executing a second-stage payload. No specific family could be identified, but the execution method is clear.

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
d21b56a7d3a8213bef500e868b8ee27a958033005d852329d82337a8680bc76e
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8056 bytes