Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f0bcb80bd360e981…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:44:37 Authoring application: Microsoft Excel
MD5: 9c185a9328d87ca2eb1bc7683eb47378 SHA-1: 84575447a0dd4fe2f749130d84ea9753481acf21 SHA-256: f0bcb80bd360e9815308b0fb6acf92bc5d9400323acc999c1459780dff92299a
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a common technique for executing arbitrary code. The 'RUN=0' in the dangerous formula API firing suggests the macro is designed to execute external commands or download payloads. The document body contains obfuscated text, further supporting a malicious intent. The lack of specific IOCs like URLs or hashes means the exact payload cannot be determined from this analysis alone.

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
370ed5b022d7690831315dda59d17b895753e8bef0f0eb51b2c8e780210adb9c
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6776 bytes