Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a4afc119a4cf6c10…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:25:48 Authoring application: Microsoft Excel
MD5: ad3b53013740257aadd4ede43e292c40 SHA-1: f09b49bae0f495a7c8e61d46b8d4414aa7509045 SHA-256: a4afc119a4cf6c109181b47cf909efbbb97764cc5db283f9d1d21761b15c4e96
140 Risk Score

Malware Insights

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

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry that utilizes dangerous functions, specifically identified as 'RUN'. This suggests the macro is designed to execute arbitrary code when the workbook is opened, likely leading to the download or execution of a secondary payload. The presence of an Auto_Open entry points to an attempt at immediate execution upon file opening.

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
b713675afdc1b3c49728afbfea4655ec2dad6aaa8cc8c7e72052544bcc06e8a5
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6685 bytes