Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c673e5e5bdd3b59d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:39:30 Authoring application: Microsoft Excel
MD5: ef7e07fbe3943ba847e9d8c646c250ef SHA-1: 90c04837f8bd8d30e785c52e96c3e3df04f727ef SHA-256: c673e5e5bdd3b59db3037dfe8e7b7e8e5e3e4309762e09c5c9d64398652cd215
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known technique for executing malicious code upon opening the document. The macro sheet contains a dangerous formula API, specifically 'RUN', suggesting it is designed to execute external commands or download payloads. The extensive obfuscated text in the document body further supports a malicious intent, likely to disguise the macro's true purpose.

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
e5596f7fb4ffdd1a5fc2a796703bde64204d0f28bec4ac74b79f175c93fd7ce6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6887 bytes