Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 da899fbfd8bbcedf…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:00 Authoring application: Microsoft Excel
MD5: da2d3c167756686856d8fed189295dfb SHA-1: d631184373a68befe7f07c88bf4d00c1b3042acd SHA-256: da899fbfd8bbcedfd6b0ac1fe4d50101776061aa9155b2ca3b0345d5914584db
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 defined name, which is a known method for executing malicious code. The macro sheet contains a reference to 'Auto_Open', suggesting it will run automatically upon opening the workbook. The presence of dangerous formula APIs further supports malicious intent, likely to download and execute a second-stage payload.

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
5ce0e4f56f9379552141ddeb8859aca062cd6b16dfd2871bb0b2be5ee97f6353		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6648 bytes

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