Office (OLE) / .XLSX malware analysis — malicious · 44e6118f1518b80f

MALICIOUS

Office (OLE) / .XLSX

36.0 KB Created: 2020-11-27 10:45:54 Authoring application: Microsoft Excel

MD5: 5e021d6a0f0c300c212c84bae5330123 SHA-1: ca8dc62f169052da26610adccff4e91d22679a05 SHA-256: 44e6118f1518b80fb6907f62f297b5e3e933f092499a71fb2e57c62b874aa1c0

140 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening the document. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. No specific family could be identified, but the execution method points to a macro-based attack.

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.

Filename	Kind	Source	Size
`xlm_macros.txt` `e3ae297f3828397675838340e40a08c624578650c2eb9672ea6d177a92eab8b7`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	6745 bytes

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