Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 24f557a1c7b5d82f…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:44:49 Authoring application: Microsoft Excel
MD5: 57e562af18148e2e87b2dfd8de3ad35e SHA-1: 55174dbcf315aa30538366f31970a338ab3dced5 SHA-256: 24f557a1c7b5d82f5e453c5126494c1a8a1dcb539e59a392910a262f6abee848
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 (XLM) macros, specifically an Auto_Open entry. This indicates the macro will execute automatically upon opening the file. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands, likely to download and run a second-stage payload. No specific IOCs were extracted, but the Auto_Open functionality is a strong indicator of malicious intent.

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
2985e9024849147d3f116ee503a05d7098793c2cbf0a2ad55b9b76f97e51e281
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6662 bytes