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

Static analysis result for SHA-256 aa66df26a5be427d…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: e02432d88963d705dc72d0a8c25a0f33 SHA-1: 1ba515b9f8091a531275dc204d317305de8ef048 SHA-256: aa66df26a5be427d325376dcc46b22d71706dbe30633c8d995aef74b850b1b01
140 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically the 'RUN' function. This strongly suggests the macro is designed to execute arbitrary commands, likely to download and execute a secondary payload. No specific family could be identified, but the technique is common for initial access.

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
2f7ee519731d38e18536b0763b08176d24c412e7231d7ad4139c793082df8c78
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8065 bytes